Boris Mayorsky, envoy to the former Yugoslavia, and Leonid Ivashov, the Defence Ministry's head of international co-operation, accused Nato, which leads K-For, of pursuing its own agenda.

In a joint statement they said Russian troops would leave K-For if its actions became "unacceptable" to Moscow.

They stressed, however, that this was not imminent.

Violence

The statement said Nato was not upholding UN resolutions relating to K-For's deployment and that the peacekeeping body had failed to stop violence against Serbs in Kosovo.

Serbs bury their dead

"None of the obligations under the resolution have been applied," said Mr Mayorsky.

"Who is responsible for this? The question must be directed at the military and political leadership of the alliance."

Mr Ivashov complained that Nato was ignoring the sovereignty of Yugoslavia by preventing Belgrade's participation in solving Kosovo's problems.

"The United States and Nato are trying to establish their own order in the Balkans, excluding the region's nations in the process," he said.

Serb exodus

Russia was strongly opposed to Nato's bombing campaign, but it eventually agreed to work with K-For.

Its participation in the Nato-led mission has been fraught with complications since its troops arrived at the airport of the Kosovo capital, Pristina, ahead of Nato forces on 12 June.

Moscow complained earlier this week that "ethnic cleansing" of Serbs was continuing in the province while Nato did nothing to stop it.

It said K-For troops were failing to take action to curb a Serb exodus from Kosovo and to deter revenge attacks by returning Albanian refugees.

At least 35,000 Serbs are thought to have fled Pristina alone since the beginning of the K-For mission.