With concern rising over the lack of adequate shelter in Kosovo, the U.N. refugee agency flew tons of warm clothing to the war-ravaged Serbian province today to help hundreds of thousands of people cope with the coming Balkan winter.

Elsewhere, Yugoslavia's independent Beta news agency reported two weekend grenade attacks on Kosovo's dwindling Serbian community.

A Russian-built Antonov 124, the world's largest transport plane, landed at Pristina's airport with 60 tons of winter underwear, coats and boots for women and children, according to Peter Kessler, spokesman for the U.N. High Commissioner for Refugees.

Last week, European Union officials said about 300,000 of the province's 1.4 million people lack adequate shelter because so many homes were destroyed during a 2 1/2-month Belgrade government campaign to purge Kosovo of its ethnic Albanian majority.

NATO-led peacekeepers entered the province June 12 after the Serbian and Yugoslav forces withdrew, but delays in committing funds and other bureaucratic hurdles have prevented a major reconstruction effort. Nighttime temperatures in mountainous parts of Kosovo are already approaching freezing.

The advent of winter adds a new dimension to a NATO and U.N. mission that has spent months trying to restore order and curb revenge attacks by ethnic Albanians angry over the brutality of the Serb-led Yugoslav offensive. Their rage also has spread to other Slavic minorities--such as Croats, Montenegrins and Bosnian Muslims--who share a common language with the Serbs.

In Belgrade, Beta said three Serbian youths were injured in Kosovo Saturday night when someone in a passing car hurled a grenade at them in the village of Lipljan, six miles south of Pristina. Beta also said a grenade was tossed into a home today in the northern town of Zubin Potok, injuring a Serbian couple.