"Since the video was first noted and tweeted out by the Russian government, I think it says something about Russia's role," Xinhua quoted White House spokesperson Jay Carney as saying at a daily news briefing.
In what was described as candid phone conversation between Victoria Nuland, US assistant secretary of state for European and Eurasian affairs, and US Ambassador to Ukraine Geoffrey Pyatt that was posted on YouTube, the pair talked about a political deal to end the months-long standoff between the Ukrainian government and the opposition.
Ukrainian President Viktor Yanukovych last month offered the premiership to Opposition Leader Arseniy Yatsenyuk and agreed to make Vitaly Klitschko, a boxer-turned-politician, deputy prime minister.
"I don't think Klitschko should go into the government," Nuland said on the call. "I don't think it's necessary. I don't think it's a good idea."
She added that she had been told UN Secretary General Ban Ki-moon was about to appoint Robert Serry, the former Dutch ambassador to Ukraine, as his representative for the East European country.
"That would be great to help glue this thing and to have the UN help glue it," said Nuland, who was in Ukraine Thursday. "And you know, fuck the EU."
Her attitude was seen as Washington's frustration with the EU, as protests have dragged on since November in Ukraine and killed at least six people.
Carney said he was not accusing the Russians of tapping US diplomatic phone calls, but "just noting that they tweeted it out".
While declining to comment on the recording's content, State Department spokesperson Jennifer Psaki did not deny its authenticity.
"I did not say it was not authentic," she said at a regular press briefing. "Certainly we think this is a new low in Russian tradecraft in terms of publicising, posting."
"I don't have any other details about the origin of the YouTube video," she added, noting Nuland had apologised to her European counterparts over the episode.
Washington's mass domestic and global spying programme, in which scores of world leaders were targeted as well as unveiled by Edward Snowden, a former National Security Agency contractor, has sparked outcries in Europe and other continents.