Technical boss Newey stated "we've got an engine which is quite a long way behind".
But Renault's engine chief said: "It's hard to have a partner who lies."
He added on French site Autohebdo: "Adrian is a charming man and an engineer without equal but he has spent his life criticising engine partners."
Red Bull have been contacted by BBC Sport for a response to Abiteboul's quotes.
The Austrian team dominated Formula 1 for four seasons between 2010 and 2013, winning the constructors' championship while Sebastian Vettel collected successive drivers' championships.
However, that dominance was ended by Mercedes and Lewis Hamilton last year.
Abiteboul added: "In addition to our problems, Red Bull has some chassis problems which don't help the situation.
"In particular, the lack of rear stability. These two problems combine to ensure the car is difficult to drive."
Chief F1 writer Andrew Benson
"The relationship between Red Bull and engine supplier Renault is clearly at its lowest ebb and it's hard to believe it's only a little over a year since they were celebrating their fourth consecutive title double together.
"Both sides have valid points. Renault have been left behind by Mercedes and Ferrari on engine performance. But equally the latest Red Bull seems not to be the team's best-ever product and Adrian Newey does have a history of being dissatisfied with engine partners, whoever they are.
"But it's hard to see the endgame here.
"Renault are scouting around with one eye on buying a team and running one themselves again. But where would Red Bull go for an engine if not Renault? Mercedes have already said no and Ferrari would probably not be keen either.
"It's not impossible that the threats made after Australia that Red Bull might quit the sport are less empty than initially believed, although they, like all teams, are contracted to F1 until 2020."
Federica Mogherini agreed with Cuban Foreign Minister Bruno Rodriguez to speed up the pace of talks
The European Union and Cuba will intensify negotiations aimed at normalising ties, EU foreign policy chief Federica Mogherini says.
Ms Mogherini hoped the two sides could sign an agreement by the end of 2015.
She was speaking after meeting President Raul Castro and Foreign Minister Bruno Rodriguez on Tuesday in the Cuban capital, Havana.
Ms Mogherini is the highest-ranking EU official to visit communist Cuba for several years.
Thaw
Her visit is seen as another sign that the island is strengthening its ties with the West, after decades of Cold War tensions.
A third of the tourists who visit Cuba each year come from the European Union
In December, Cuba and the United States announced they would be improving their ties, which have been frozen since 1961.
Russian Foreign Minister Sergei Lavrov also met Cuban leaders in Havana on Tuesday and praised the thaw in Cuba-US ties. Cuba was allied to Moscow during the Cold War.
While EU-Cuban relations never reached the levels of animosity of those between Cuba and the US, the EU did have economic sanctions in place against the island until 2008.
Under its 1996 Common Position, the EU had moreover restricted its ties with the Cuban government until reforms were made in areas such as democracy, a multi-party system, human rights and fundamental freedoms.
In February 2014, the EU announced it would enter into negotiations with Cuba to restore full bilateral relations.
However, the two sides only held three meetings in 2014, prompting Ms Mogherini to call the pace "slow".
The Cuban foreign minister and Ms Mogherini are due to meet again at the Summit of the Americas in two weeks time and on 22 April in Brussels.
The EU is Cuba's second-biggest trading partner after Venezuela and also represents a major source of investment.
One-third of tourists to the island every year come from the EU.
An activist defaces a sign saying 'Nemtsov Bridge' at a memorial site in central Moscow
A memorial in central Moscow to the murdered Russian opposition leader Boris Nemtsov has been vandalised.
Slogans and insults were scrawled on photographs of the politician and a street sign saying "Nemtsov Bridge" was defaced.
An obscure nationalist group, which is sympathetic to pro-Russian rebels in Ukraine, said it was responsible.
Mr Nemtsov was shot on 27 February while walking with his girlfriend on the bridge, near the Kremlin.
Russian President Vladimir Putin has condemned the murder and vowed to find the killers.
'Scumbags'
Pictures emerged on social media, apparently taken by the vandals themselves, showing people desecrating tributes marking the spot where Mr Nemtsov was attacked.
A pro-Kremlin organisation called South-East Ukrainian Civil Movement (SERB) later claimed responsibility, saying its actions were a response to calls to rename Moscow's Bolshoy Moskvoretskiy bridge in Mr Nemtsov's honour, according to Russian news website Lenta.ru.
Photos of Mr Nemtsov and tributes to him were vandalised - one sticker says "traitor to Russia's interests"
Allies of Mr Nemtsov, a former deputy prime minister and veteran liberal politician, condemned the damage.
"Some cowardly scumbags have trashed Nemtsov's memorial," Ilya Yashin, co-founder of his political party, wrote on Twitter.
Mr Nemtsov's supporters have said the killing was linked to his criticism of the Kremlin.
He was killed days before a march he had been organising against the conflict in Ukraine.
Mr Yashin told the BBC earlier this month that a report Mr Nemtsov had been compiling on Russia's role in the crisis would be released in April.
Officials have not revealed a motive for the murder.
Several men from the Caucasus region have been arrested for the murder, prompting suggestions of an Islamist link to the attack. One of those charged has said he was forced into a confession.
Ukraine's military has been battling pro-Russian separatist rebels in the country's east since April 2014.
The Ukrainian government, Western leaders and Nato say there is clear evidence that Russia is helping the rebels with heavy weapons and soldiers.
Independent experts echo that accusation. Moscow denies it, insisting that any Russians serving with the rebels are "volunteers".
A government task force ruled last year it rightfully belonged to his heirs.
Germany's Culture Minister Monika Gruetters has signed an agreement paving the way for the masterpiece to be handed back.
The deal must now be approved by a court dealing with Gurlitt's estate.
Legal disputes
The Bavarian authorities seized some 1,280 artworks from Gurlitt's Munich flat as part of a tax evasion probe in February 2012.
The find triggered legal disputes surrounding works seized by the Nazis in the 1930s and 40s.
Gurlitt died in May last year aged 81, having named the Bern museum in Switzerland as his "sole heir". He had agreed to help authorities discover which works had been stolen.
But German officials said three artworks - including Femme Assise by Henri Matisse - would be returned immediately.
A similar agreement was signed last week for the return of a painting by Max Liebermann, Zwei Reiter am Strand [Two Riders on the Beach].
Artworks going home
Max Liebermann's Two Riders on the Beach is also due to be sent back to the family of the original owners
Henri Matisse's Femme Assise [Seated Woman] was looted from Jewish art dealer Paul Rosenberg and is set to be returned to his descendants, who had been looking for the piece when Gurlitt's hoard was discovered
Max Liebermann's Two Riders on the Beach is said to have been seized from industrialist and avid art collector David Friedmann "as a consequence of the Nazi persecution of Jewish citizens". His great-nephew, David Toren, had taken legal action against Germany for its restitution
Carl Spitzweg's Playing the Piano is to be returned to the heirs of music publisher Henri Hinrichsen, who was murdered at Auschwitz in 1942
Gurlitt's father, Hildebrand Gurlitt, was ordered by Adolf Hitler to deal in works that had been seized from Jewish families, or which the Nazis considered "degenerate" and had been removed from German museums in the 1930s and 1940s.
Matisse's Femme Assise, painted in 1921, was taken from Jewish art dealer Paul Rosenberg in Paris in 1941.
His family had been searching for it until it turned up in Gurlitt's flat.
Media captionAmanda Knox and Raffaele Sollecito were both convicted for the second time last year, as Gavin Lee reports
Italy's top court has delayed a decision on whether to uphold the convictions of Amanda Knox and Raffaele Sollecito for the 2007 murder of British student Meredith Kercher.
The court will hear from Sollecito's defence team on Friday before the judges give their verdict.
Former lovers Knox and Sollecito were convicted for the second time in 2014.
They have maintained their innocence throughout and have already served four years in prison.
The Court of Cassation in Rome is due to confirm the guilty verdict or overturn it - either ordering another trial or effectively bringing about an acquittal.
A definitive conviction would trigger complicated attempts to extradite American Knox, who lives in Seattle in the US.
Sollecito, from Bari, southern Italy, has remained in the country, and attended the court with his new girlfriend on Wednesday.
'Remember Meredith'
Speaking before the hearing, the Kercher family's lawyer, Francesco Maresca, said they hoped the court's decision would bring an end to the judicial process.
"It's a case that has gone on for so many years now," he said.
"They hope that this will be the final stage of this judicial process and they will at last... be able to remember Meredith outside of the court room [process]."
Meredith Kercher, 21, was found with her throat cut
Leeds University student Meredith Kercher, 21, from Coulsdon, south London, was found dead in the flat she shared with Knox, now 27, in Perugia, central Italy, where both women were studying.
Her partially-clothed body was found under a duvet in her bedroom, which had been locked from the inside. Her throat had been cut.
Prosecutors claimed she was killed as part of a bungled sex game. Knox and Sollecito, 30, were convicted of the murder by a trial court in Perugia in 2009.
They were freed in 2011 after an appellate court overturned the convictions.
Sollecito and his current girlfriend Greta Menegaldo arrived at the court in pouring rain on Wednesday morningAmanda Knox, who appeared on American TV last year, could face extradition
The Court of Cassation rebuked the appellate judge's reasoning and last year an appeals court in Florence sentenced Knox to 28 years and Sollecito to 25 years.
The latest ruling could confirm that conviction or overturn it - and either order yet another trial or effectively acquit the pair, although legal experts say the last option is unlikely.
Rudy Hermann Guede, born in the Ivory Coast, who opted for a fast-track trial, is serving a 16-year sentence for his role in the murder.
The high-profile case has inspired books and at least two films, and Kercher's family has said Meredith, the real victim, risked being forgotten.
Originally portrayed as a fast-living partygoer, Knox came to be seen in much of her home country as a victim of a botched investigation and an unwieldy justice system.
Her lawyer, Luciano Ghirga, said she was "waiting anxiously" for Wednesday's verdict, according to AP.
Two senior Ukrainian officials have been arrested during a cabinet meeting as part of an anti-corruption crackdown, hours after a powerful regional governor was sacked.
The head of Ukraine's state emergencies service, Serhiy Bochkovsky, and his deputy Vasyl Stoyetsky were handcuffed by police at the televised meeting.
They are suspected of involvement in high-level corruption.
Earlier, Ukraine's president sacked a billionaire governor, Ihor Kolomoisky.
Mr Kolomoisky had been running the key industrial region of Dnipropetrovsk and had financed armed volunteers to fight pro-Russian separatists in the east. He had been vying with President Petro Poroshenko for control of the Ukrnafta energy company.
The two arrests shown on TV on Wednesday were connected to illegal kickbacks involving procurement contracts, Interior Minister Arsen Avakov told the cabinet meeting.
Prime Minister Arseniy Yatsenyuk, quoted by Reuters news agency, said that "when the country is at war and when we are counting every penny - they steal from people and the state.
"This will happen to everyone who breaks the law and sneers at the Ukrainian state."
The arrest order was read out to the two officials, who were then handcuffed and led away
'Offshore accounts'
Mr Avakov said he was also dismissing all regional heads of the state emergencies service, as they were suspected of involvement in a corrupt scheme that had diverted money offshore.
Speaking on Ukrainian TV, he said officials at the service had used a private company to transfer funds "to a non-resident of Ukraine, a Jersey-based offshore company".
From there, he said, money went to "another private company owned by Stoyetsky and Bochkovsky, after which this money was divided between card accounts opened, in particular, in Cypriot banks". He showed printouts of what appeared to be card statements.
Mr Yatsenyuk's government is under pressure from Western lenders to prove that it is cleaning up government finances, as Ukraine has been plagued by high-level corruption since independence in 1991.
Last month the International Monetary Fund agreed a $17.5bn (£11.5bn) loan to Ukraine as part of a new economic reform programme. Western loans to Ukraine total $40bn, spread over four years.
Armed stand-off
Another senior official, the head of state-run Southwestern Railways Oleksiy Kryvopishyn, was sacked on Wednesday. It is Ukraine's second-largest railway company, mainly serving central areas including Kiev.
Ihor Kolomoisky is widely credited with helping to halt the advance of pro-Russian rebels in the east
President Poroshenko's dismissal of the oligarch Ihor Kolomoisky is seen as a clash between business rivals vying for control of energy assets.
Armed men suspected of links to Mr Kolomoisky had briefly occupied the offices of state-owned Ukrnafta and its subsidiary UkrTransNafta.
Mr Kolomoisky was reportedly unhappy after parliament passed legislation aimed at weakening his influence.
Mr Poroshenko's office named Valentyn Reznichenko as the new acting governor of the Dnipropetrovsk region.
Mr Kolomoisky - who is estimated to be worth more than $2bn (£1.3bn) - has helped President Poroshenko by keeping order in Dnipropetrovsk and preventing pro-Russian rebels from advancing into the region. It lies near rebel-held areas of Donetsk and Luhansk regions.
A senior Russian politician, Federation Council speaker Valentina Matviyenko, spoke scathingly about Ukraine's "war of the oligarchs" on Wednesday.
"This situation shows that Ukraine has no statehood and is not a sovereign state", she said, predicting "further schisms within Ukraine".
French investigators say usable data has been extracted from the cockpit voice recorder of Germanwings 4U 9525 but it has so far yielded no clues as to the cause of the plane's crash.
They said the plane hit the ground in the French Alps at great velocity, suggesting no explosion in flight.
Flight 4U 9525 from Barcelona to Duesseldorf crashed after an eight-minute rapid descent on Tuesday.
The French, German and Spanish leaders visited the crash site on Wednesday.
Remi Jouty, the director of the French aviation investigative agency, said there were sounds and voices on the cockpit voice recorder but that it was too early to draw any conclusions.
He said he hoped investigators would have the "first rough ideas in a matter of days" but that the full analysis could take weeks or even months.
There had been earlier reports that the second black box - the flight data recorder - had been found. But Mr Jouty said this was not the case.
'Flying to the end'
Mr Jouty said the plane's last communication was a routine one with air traffic control.
The plane confirmed instructions to continue on its planned flight path but then began its descent a minute later.
Analysis by Richard Westcott, BBC Transport Correspondent
The "black box" cockpit voice recorder is pretty battered but the devices are bomb-proof, literally, so investigators should still be able to listen to what happened on board.
The large, orange cylindrical part in the middle holds the memory boards that record the pilots' voices, and that looks intact to me.
The critical question now is, were the pilots speaking during those lost eight minutes when the aircraft dropped from 38,000ft to the ground?
If they're quiet, investigators will know they were unconscious, and that suggests a major decompression took place on board. That's when a hole in the fuselage lets all the air out. It's not necessarily fatal, if the pilots can get their oxygen masks on in time, something they train for, but if they were knocked out, it would explain the lack of a mayday call or any obvious attempt to steer the stricken aircraft to the nearest runway.
Mr Jouty said controllers observed the plane beginning to descend and tried to get back in contact with the pilots but without success.
He ruled out an explosion, saying: "The plane was flying right to the end."
Mr Jouty said: "At this stage, clearly, we are not in a position to have the slightest explanation or interpretation of the reasons that could have led this plane to descend... or the reasons why it did not respond to attempts to contact it by air traffic controllers."
'Shoulder to shoulder'
Germanwings chief Thomas Winkelmann said 72 of the 144 passengers were German citizens. The victims included 16 pupils returning from an exchange trip. Spain's government now says 51 of the dead were Spanish.
UK Foreign Secretary Philip Hammond confirmed that three Britons were on board. Other victims were from Australia, Argentina, Iran, Venezuela, the US, the Netherlands, Colombia, Mexico, Japan, Denmark and Israel.
However, there may be some duplication because of dual citizenship.
Earlier, French President Francois Hollande, German Chancellor Angela Merkel and Spanish Prime Minister Mariano Rajoy gave a press conference after visiting the site of the crash.
Mr Hollande told his counterparts: The French people are here shoulder to shoulder with you during this ordeal. Everything will be done to find, identify and hand back to the families the bodies of their loved ones."
Both he and Mrs Merkel said they would do everything they could to find the cause of the crash.
Mrs Merkel added: "Francois, I would like to thank you on behalf of millions of Germans for this example of German-French friendship."
In a press briefing later, Carsten Spohr, CEO of Lufthansa, which owns Germanwings, said this was "the darkest hour of 60 years of Lufthansa".
He added: "We cannot understand how an airplane in perfect technical condition with two such trained pilots was involved in such a terrible accident."
At the scene: James Reynolds, BBC News, Seyne les Alpes
French gendarmes here have taken over a large part of this valley on the outskirts of town. One van with sirens escorted in a white trailer bearing the words "Mobile Criminal Investigation Laboratory".
Emergency workers in fluorescent jackets say that they want to work as quickly as they can.
"We cannot leave the victims a week in the mountains," said Roy Xavier from Civil Security.
But victims' families will have a long wait for the bodies to be returned to them. The Prosecutor of Marseille told reporters that it may be several weeks before all the victims are identified.
