The State Department's top official for Europe apologized today after being caught making a crude and dismissive remark about the European Union, one of America's top allies.

The spokeswoman hinted that Russia had taped and leaked the phone call, calling it "a new low in Russian tradecraft."

A leaked phone call posted on YouTube caught Assistant Secretary of State for European and Eurasian Affairs Victoria Nuland saying "f-k the EU" while speaking with U.S. ambassador to Ukraine Geoffrey Pyatt. Nuland used the expletive while complaining that the European Union hasn't done enough to get Ukraine to break an agreement with Russia and instead sign on to a trade agreement with Europe.

Dmitry Loskutov, an aid to Russian Deputy Prime Minister Dmitry Rogozin, was among the first on Twitter to link to the video, which surfaced Tuesday. Along with the video link, Loskutov tweeted, "Sort of controversial judgment from Assistant Secretary of State Victoria Nuland speaking about the EU."

State Department spokeswoman Jen Psaki said today that Nuland has apologized for the remark and Psaki criticized the Russians for being quick to tweet a link to the recording.

"This is something [the Russian government] has been actively promoting, posting on, tweeting about and certainly that we feel represents a new low," Psaki said during the State Department daily briefing, though she would not explicitly blame the Russians for recording or leaking the call.

Psaki would not say to whom Nuland apologized.

The four-minute conversation was about a Jan. 25 offer by Ukranian President Viktor Yanukovich to two opposition leaders, who want him to sign the EU deal, to become prime minister and deputy prime minister.

Nuland said she wanted one of the two leaders to join the government, but that another was too inexperienced and should stay outside officialdom.

Psaki said it's common for diplomats to express private opinions that may not reflect what ultimately becomes the government's official view. "What do you think happens behind closed doors when people are discussing issues internally through the interagency [process]?" she asked.

Asked if Nuland's expletives reflected a wider frustration within the State Department towards the EU, Psaki said Nuland's background of working on a Soviet fishing trawler in her early 20s meant she had a certain comfort level with expletives: "[S]he learned how to perfect, perhaps, certain words in a couple of languages. So perhaps it speaks to that more than a pervasive viewpoint."

Assistant Secretary of State for European and Eurasian Affairs Victoria Nuland testifies before the Senate Foreign Relations Committee on the situation in the Ukraine, during a hearing on Capitol Hill in Washington, DC, Jan. 15, 2014. Saul Loeb/AFP/Getty Images.