The withdrawal late on Friday comes after the worst violence in the Serbian province for several months.

The head of the international monitors in Kosovo, William Walker, is in Podujevo to try to convince Serbian security forces and ethnic Albanian rebels to respect the ceasefire.

Paul Welch reports on Friday's fighting

His visit was prompted by heavy fighting on Thursday as the Kosovo Liberation Army abandoned its ceasefire in response to an attack on northern Kosovo villages by 100 Yugoslav army tanks.

Two columns of Yugoslav military vehicles, each consisting of tanks and armored personnel carriers, returned to their base late Friday.

Ambassador Walker had separate meetings with Serbian military commanders and a local leader of the rebel Kosovo Liberation Army.

OSCE spokesperson Jurgen Grunnet: "The tanks have been pulled back"

But despite Mr Walker's intervention, the BBC Balkans Correspodent, Paul Wood, says it's still too early to say if the fighting is over.

The monitors' mission was originally established simply to report on whether both sides were keeping to United Nations resolutions, but analysts say it is already clear that they will have to take a much more active role, something acknowledged by Mr Walker when he described the monitors as the last best hope for peace in Kosovo.

Paul Wood assesses Friday's events in Kosovo

Western officials say the latest fighting puts both sides in breach of UN resolutions.

The KLA has said it would be willing to re-establish a truce if the Yugoslav security forces ceased their operations.

Leaders of the OSCE monitoring team say they have sent a "very strong protest" to Yugoslav authorities after a Serb policeman told a team of verifiers Thursday he would shoot if they didn't immediately leave the area outside a military barracks in Podujevo they were watching.

Warning over force

The Russian foreign minister, Igor Ivanov, has warned the West against any use of force in Kosovo, saying this would only play into the hands of extremists.

He called on both sides in the conflict to exercise "maximum restraint".

"The attempts to shift the accent from promoting a political settlement to the use of force ... are unacceptable," a statement from the ministry said.

"The continuation of provocations and hostile actions carries a threat to the already fragile balance in the region," it continued.