German Chancellor Angela Merkel has strongly criticised a comment made by a senior US diplomat about the European Union's role in Ukraine.
The German leader considers the comment by the top US diplomat for Europe, Victoria Nuland, to be "absolutely unacceptable," Mrs Merkel's spokeswoman says.
In a leaked recording, a voice resembling Ms Nuland's is heard saying "F*** the EU," suggesting that the EU's position on Ukraine should be ignored.
The spokeswoman told reporters in Berlin today that Germany believes EU foreign policy chief Catherine Ashton "is doing a marvellous job" trying to mediate between the government and opposition in Ukraine.
The comment emerged after a phone call involving Ms Nuland was apparently bugged.
US officials say they strongly suspect Russia of leaking the conversation.
The suspicions were aired last night after audio of the call was posted to the internet and amid continuing criticism of the US in Europe and elsewhere over National Security Agency (NSA) spying on foreign leaders.
They also came as the Russia-hosted Winter Olympics opened under tight security to prevent possible terrorist attacks and highlighted distrust between Washington and Moscow that has thrived despite the Obama administration's attempt to "reset" relations with the Kremlin.
The White House and State Department stopped just short of directly accusing Russia of surreptitiously recording the call between Ms Nuland, and the US ambassador to Ukraine, Geoffrey Pyatt.
But both took pains to point out that a Russian government official was the first or among the first to call attention to the audio of the conversation that was posted on YouTube. The State Department said the incident marked a "new low in Russian tradecraft".
White House spokesman Jay Carney pointed to the Russian official's tweet and Russia's clear interest in what has become a struggle between pro-Moscow and pro-Western camps in the former Soviet Republic.
"I would say that since the video was first noted and tweeted out by the Russian government, I think it says something about Russia's role," he told reporters.
He would not comment on the substance of the conversation, which also discusses of various Ukrainian opposition figures.
An aide to Russian deputy prime minister, Dmitry Rogozin, was among the first to tweet about the YouTube video, which shows photos of Ms Nuland and Mr Pyatt and is subtitled in Russian.
In the tweet, posted some seven hours before existence of the video became widely known, Mr Rogozin's aide, Dmitry Loskutov, said: "Sort of controversial judgment from Assistant Secretary of State Victoria Nuland speaking about the EU."
Today Mr Loskutov said neither he nor the Russian government played a role in leaking the tape. H e was surfing a social networking website when he came across the video. He said his decision to repost the video had no connection to his work for the Russian government.
State Department spokeswoman Jen Psaki did not dispute the authenticity of the recording and said that Ms Nuland had apologised to EU officials for her remarks.
The practice of eavesdropping on the phone calls of other governments - even between allies - was the first diplomatic fallout from the publication of documents taken by former NSA analyst Edward Snowden.
The documents he took and that were published in such newspapers as The Washington Post, the New York Times and The Guardian showed that the US listened in to the phone calls of allies such as German Chancellor Angela Merkel.
Ms Merkel was outraged, and part of the US response was that such practice is common on both sides around the world.