Washington's top diplomat in Europe on Friday refused to comment on a leaked phone conversation in which she used the f-word in regards to the EU's handling of the Ukraine crisis.
Ukrainian President Viktor Yanukovych shakes hands with US Assistant Secretary of State Victoria Nuland in Kiev on Thursday.
The United States is seeking to contain the damage after the embarrassing leak of a phone call in which Nuland allegedly used an obscenity while discussing the EU response to the Ukrainian crisis which has pitted Russia against the West.
"Fuck the EU," Nuland allegedly said in what appeared to be a phone conversation with US ambassador to Kiev, Geoff Pyatt, which was uploaded onto YouTube accompanied by Russian-language captions.
"It was pretty impressive tradecraft. (The) audio quality was very good," Nuland said on Friday.
In the phone call, Nuland was heard discussing boxer-turned-politician Vitali Klitschko and another opposition leader, Arseniy Yatsenyuk.
"I don't think Klitsch should go into the government," she apparently said.
"I think Yats is the guy who's got the economic experience, he's got the governing experience," she adds.
A spokeswoman for Klitschko said: "Our position is, it does not make sense to comment conversations whose authenticity has not been confirmed by anyone."