* U.S. diplomat admires spying tradecraft over leaked call
* Says leak will not harm ties with opposition leaders (Adds quotes, background)
By Richard Balmforth
KIEV, Feb 7 (Reuters) - A U.S. diplomat whose telephone conversation about the political crisis in Ukraine was leaked on the Internet said on Friday that the recording was "pretty impressive tradecraft" but suggested the leak would not harm U.S. ties with the Ukrainian opposition.
Assistant Secretary of State Victoria Nuland also denied a Russian claim that anti-government militants are trained on the grounds of the U.S. embassy in Ukraine, calling it "pure fantasy".
The conversation between Nuland and the U.S. ambassador to Ukraine revealed an embarrassing exchange about the relative merits of Ukraine's opposition leaders and their fitness for high office in a reformed Ukraine and included a crude American swipe at the European Union.
U.S. officials have pointed the finger at Russian intelligence for being behind the audio clip, which was posted on Tuesday but gained wide circulation on Thursday, as an attempt to derail Western diplomacy aimed at helping bring a peaceful end to the crisis in the ex-Soviet republic.
Nuland on the clip referred to getting the United Nations involved in a political solution in Kiev.
"So that would be great, I think, to help glue this thing and have the U.N. help glue it and you know ... fuck the EU," she said in the recording, which was accompanied by still pictures of people mentioned in the call.
But Nuland on Friday clearly sought to play down the incident and not allow it to turn into a diplomatic incident that would spoil U.S. relations with Russia in other international areas.
"I am not going to comment on private diplomatic conversations. But it was pretty impressive tradecraft. The audio was extremely clear," she told a news conference.
On the audio clip, Nuland is heard telling U.S. Ambassador Geoffrey Pyatt that she doesn't think that Vitaly Klitschko, the boxer-turned-politician who is a main opposition leader should be in a new government.
But Nuland, replying to questions, indicated she did not feel the incident would spoil relations with opposition leaders, who also include former Economy Minister Arseny Yatsenyuk and far-right nationalist Oleh Tyahnibok, some of whom are regarded by Western government as future key politicians in a reformed Ukraine.
"They (the opposition leaders) know exactly where we stand in respect of a non-violent solution to the problem," she said.
Of relations with Russia, she said Washington and Moscow had "very deep, very broad and complex" discussions on a range of international issues including Iran and "frank and comradely discussions" with Moscow on Ukraine.
"Our message has been that we all - Ukrainians, Russians, Americans, all Ukraine's neighbours - have an interest in a peaceful, stable democratic Ukraine," she said.
But she had sharp words for Sergei Glazyev, a Kremlin aide who accused the United States of arming Ukrainian rebels and who warned that Russia could intervene to maintain the security of its neighbour
Dismissing his comments as "pure fantasy" she said: "He could be a science fiction writer", adding that the United States had an absolutely transparent policy on Ukraine.
She said the United States sought defuse street tension to end the possibility of any further violence, and supported the formation of a "national technical government".
"We want Ukraine back to economic health, back to support from the IMF, back to Europe and back to free and fair elections," she said.
(Reporting Richard Balmforth)