A day after the Serbian premier promised to withdraw special police units from Kosovo as demanded by NATO, Serb forces launched new attacks Tuesday south of the provincial capital, ethnic Albanian sources said.

Serbian Premier Mirko Marjanovic said Monday that government forces had crushed the secessionist Kosovo Liberation Army and that special police units would be returned to their barracks. It was unclear if any police had done so Tuesday.The Kosovo Liberation Army is fighting for Kosovo's independence. Kosovo is located in southern Serbia, Yugoslavia's dominant republic. Most ethnic Albanians, who make up 90 percent of Kosovo's 2 million inhabitants, favor independence.

Marjanovic warned that troops could be sent back to the field if rebels resumed attacks on Serb police.

NATO recently stepped up plans for airstrikes against Serb forces after repeated warnings that it would attack unless violence ends in the province.

The Albanian-run Kosovo Information Center reported heavy Serb attacks Tuesday around the towns of Stimlje and Urosevac, about 18 miles south of Pristina, Kosovo's capital.

The Information Center said smoke billowed from several villages and that 700 civilians were trapped in at least one village.

There was no statement from Serb sources. The Information Center reports could not be independently confirmed.