The grave near Urosevac, 20 miles south of the province's capital, Pristina, is reported to contain the bodies of about a dozen Albanians killed in the Serbian government's offensive against pro-independence fighters in the spring.
Mass graves are a burning topic in Kosovo and Serbia, as Serbia's reported atrocities against Kosovo's mostly Albanian population last year prompted the West to threaten Belgrade with air strikes. Belgrade was forced to withdraw most of its troops.
Sandy Blyth, a spokesman for the Organisation for Security and Co-operation in Europe, said: "The information is on an apparent, alleged mass grave of 11 women and children who were apparently killed in the summer."
Serbia's deputy Prime Minister, Vojislav Seselj, denounced the monitors working for the OSCE for investigating "non- existent Albanian mass graves around Urosevac". Mr Seselj said: "Western powers, Nato and Albanian terrorist bands are conducting a joint action in Kosovo."
At the same time, Belgrade threatened the work of a Western medical charity, accusing it of supplying arms to Kosovo's Albanians guerrillas. Vukasin Andric, Serbia's health minister for Kosovo, said the Paris-based group Medecins Sans Frontieres (Doctors Without Frontiers) "has abused their mission as they have been caught trying to smuggle in and conceal arms for ethnic Albanian terrorists". The charity's head in Yugoslavia, Tim Boucher, denied the charge, which he said came out of the blue.
The Serbian authorities have repeatedly complained that the presence in Kosovo of OSCE monitors, in place to observe a US-brokered truce between Belgrade and the Albanians, has merely allowed Albanian guerrillas to regroup and strengthen their control over Kosovo.
Another two Albanians were shot dead yesterday at a petrol station in Vitina, 25 south-east of Pristina, although it was not clear whether they were "collaborators" murdered by the guerrillas of the Kosovo Liberation Army or victims of Serb revenge squads.
Belgrade's fear that the province is continuing to slip out of its control will have been strengthened by the first broadcasts of a KLA-run radio station - Radio Free Kosovo, "Kosova e Lire"- in "liberated" territory in the province and the first news items from a KLA press agency - Kosova Press - published yesterday.
The failure of the American-brokered truce to lead to substantive talks on Kosovo's constitutional status in or outside Serbia makes it certain that the province will be plunged back into more fighting in the spring once the thaw starts.
In Washington, James Rubin, the US State Department spokesman, said yesterday: "There is not that much time left for a negotiated solution before we face the prospect of renewed and very dangerous conflict this spring."Reuse content