Russia threatened on Tuesday to release a recording of a disputed conversation, putting the EU on the spot over allegations that President Vladimir Putin threatened he could capture Kiev in two weeks.
Italy's La Repubblica newspaper reported on Monday a summary of a debate at last weekend's EU summit in which European Commission chief Jose Manuel Barroso recounted his telephone conversation with Putin.
The paper said the Kremlin strongman declined to answer questions about Russian troops operating in Ukraine and Barroso quoted Putin as threatening: "If I wanted I could take Kiev in two weeks."
A Putin aide said on Tuesday that the comments taken out of context.
"Whether these words were said or not I believe the quote that you cite has been taken out of context and had a completely different meaning," aide Yuri Ushakov told journalists.
But a European Commission spokesman later said "we have nothing to add" to a Friday statement on the phone call, in which the conversation was described as "a very frank exchange of views".
That didn't satisfy the Kremlin.
Russia's EU ambassador Vladimir Chizov has now written to Barroso, warning it will release a recording of the talk to "clear up misunderstandings" over the call, Russia's Interfax news agency reported.
"...in order to clear up misunderstandings we are ready to release the contents (of the call) if you don't inform us of your disagreement within two days," said the letter, a copy of which Interfax obtained.
Putin's aide Ushakov had sharply criticised Barroso, saying discussion of the content of their call "goes beyond the framework of diplomatic practice" and "is simply not worthy of a serious political figure".