PRISTINA, Yugoslavia (AP) _ Using bulldozers, international forensic experts began unearthing a field Friday in southwest Kosovo where the bodies of 50 civilians killed by Serb forces are believed to be buried.

The 15 forensic experts declined to speak to reporters in Ljubizda, the town southwest of Pristina where the field lies. But Abedin Ademi, 67, a farmer whose field borders the area, said the grave contained bodies of ethnic Albanians killed in April by Serb forces.

The mass grave's existence was first revealed Thursday in London by British Foreign Secretary Robin Cook. He offered no details, beyond saying that 50 bodies were found buried in a garbage dump in the village.

The discovery of another mass grave believed to contain ethnic Albanians is bound to fuel the already strong anti-Serb feeling among Kosovo Albanians.

The political leader of the Kosovo Liberation Army, Hashim Thaci, has urged an end to revenge-taking against Serbs and urged Kosovo Serbs to return to the province.

But his comments were sure to be ignored by Serbs in Kosovo and elsewhere, who blame the KLA for the wave of anti-Serb violence since NATO bombing ended in June.

Most of Kosovo's prewar population of 200,000 Serbs have fled since then, amid dozens of killings, abductions and other violence directed against them to avenge the deaths of more than 10,000 ethnic Albanians during the 18-month Serb crackdown.

Also Friday, NATO announced that peacekeepers have found hundreds of weapons hidden in a village near the Albanian border. The discovery came just two weeks before the Sept. 19 deadline for the KLA to disarm.

Among the weapons found Thursday were some 250 Kalashnikov rifles and 50 machine guns as well as other explosives and ammunition. Peacekeepers discovered the cache in the village of Rogovo, about six miles from the Albanian border, Maj. Roland Lavoie said.

Lavoie did not say whether the weapons belonged to the KLA, which smuggled in arms from Albania during the Serb crackdown.

In other developments Friday, the United Nations said it was replacing the Yugoslav dinar with the German mark and other Western currencies in the province, although Kosovo remains officially a part of Yugoslavia. U.N. officials said authorities in Belgrade were not consulted before the decision was made.

And in Pristina, the provincial capital of Kosovo, a British soldier removed a hand grenade from a truck parked outside the U.N. police building, 200 yards from the office of U.N. mission chief Bernard Kouchner.