General Radovan Lazarevic, commander of the army's Pristina Corps, told the Nedeljni Telegraf newspaper that Belgrade would send in the troops if the international community failed to respect the terms of the deal that ended the conflict over the province.
"If the international community refuses to implement what has been agreed, we will have to use force to reclaim our territory," he said.
In the first statement by a Yugoslav official openly contemplating a forcible return, he said he and his men "collectively and constantly think about our corps being again engaged in Kosovo".
Units of the Pristina Corps are massed near the Kosovo border and "are working on their combat readiness" General Lazarevic said.
The warnings came after two Serbs were killed when up to 10 mortar rounds were fired at their village, Donja Budriga, near the town of Gniljane in eastern Kosovo on Tuesday night. It was the most serious of recent attacks in eastern Kosovo, according to K-For, the Nato-led peace-keeping force.
President Slobodan Milosevic reiterated on Tuesday his demand for the return of Yugoslav security forces to Kosovo. The UN-backed agreement that ended the air war against Serbia stipulated that a small number of Yugoslav soldiers and police should be allowed back but did not specify when.
But for all the general's bluster, a full scale invasion of Kosovo appears unlikely at the moment. Serbia's economy is already shattered after Nato's air war and the impact of years of economic sanctions.
Civilian morale and fuel supplies are low and any attempt at a nationwide draft for the necessary manpower to re-capture Kosovo would be unlikely to produce the numbers necessary.