The Kosovo government is being undermined by the prospect of a delayed United Nations decision on the future of the province, according to Agim Ceku, prime minister.
He says the delay could spark renewed conflict in the Balkans.
Mr Ceku told the Financial Times that Russia's stance on granting Kosovo independence was hardening and that he had received no guarantees on a recent visit to Washington.
But he believed there remained full international support for independence and hoped that the Contact Group of nations, which oversees negotiations on Kosovo's future, would fulfil its September pledge to resolve by the end of the year the last question remaining from the disintegration of Yugoslavia.
Efforts to "make things easier" for Serbia were creating pressures for a delay, he said, and should be overcome by imposing a solution on Belgrade.
"The people of Kosovo have heard the Contact Group's statement that the process will be finished by the end of the year," Mr Ceku said.
Any delay would cause "great disappointment, loss of credibility in the -process . . . loss of credibility of our government. There would be political in-stability."
Since Slobodan Milosevic's Serb forces were driven from Kosovo by a Nato bombing campaign in 1999, the province has been a ward of the UN. In a referendum at the end of the month, Serbs will vote on a draft constitution proclaiming Kosovo an "integral part" of Serbia.
Martti Ahtisaari, the UN envoy responsible for the Kosovo talks, has hinted that snap Serbian elections could push a final-status decision back into the new year. Kosovo fears there will be a compromise granting it almost total autonomy but stopping short of full -independence.
Mr Ceku's meetings with British ministers in London this week produced fresh declarations of support. But diplomatic sources said the US, France and Britain would have to work hard to assuage Russian and -Chinese sensitivities over setting a precedent for -secession before the Kosovo decision came before the UN Security Council.
Mr Ceku, who travels to Paris next week, has had no reply to his request to visit Moscow. Western diplomats believe the Kremlin may be keeping its intentions unclear in order to exploit the secessionist ambitions of South Ossetia and Abkhazia without alienating traditional Serb allies.
But Mr Ceku wants to convince Russia that Kosovo is a unique case. About 10,000 ethnic Albanians died in "ethnic cleansing" during the 1998-99 war.