And When they use force, we will attack them." Nato says the Serbs have been warned to be restrained.On the front line, a series of small trenches snaking across the hills, the silence is so complete the red and black Albanian flag can be heard beating against its staff in the breeze Guerrillas pose with grenade launchers for the cameras. There has been a little shooting, one said, but by and large the ceasefire was holding.Commander Rrebeli waves the document in his hands "This is just a piece of paper to me," he says. "The Serbs have broken ceasefires so often I don't believe in them." In fact, an earlier ceasefire was already technically in force before this one was signed, despite the regular fighting Both sides claim the other broke it. The front line runs south from here, down from the deserted hills and through the centre of populated villages.It is impossible to get an accurate picture of the views of civilians in rebel-held territory, of how strongly they are likely to oppose the Serbs' arrival. But it appears many villagers support the rebels, and despise the Serbs. The Kosovo war spread here, and Albanians here died at the hands of Slobodan Milosevic's security forces. "The West has betrayed us," Commander Rrebeli says angrily.The Nato allies were regarded as saviours here until a week ago.

Now many of the rebels are shocked and disillusioned that the foreigners who liberated them are siding with the Serbs. On the road to Pristina, two American peacekeepers sit at a checkpoint. A steady stream of young men pass, to "visit friends" in the buffer zone Many may be joining the rebels. The Serbs accuse the peacekeepers of failing to police the border and allowing the rebels to take control in the buffer zone. Belgrade is angry the peacekeepers are not going into the buffer zone to clean up the rebels, but sending Serbian troops instead. And no one is certain how volatile a situation they are walking into..

Elite Yugoslav army troops today moved into a buffer zone overrun by ethnic Albanian forces, under terms of a NATO-endorsed plan to cap cross-border violence that threatens to expand into a new Balkan war. Elite Yugoslav army troops today moved into a buffer zone overrun by ethnic Albanian forces, under terms of a NATO-endorsed plan to cap cross-border violence that threatens to expand into a new Balkan war. In columns of trucks and armoured personnel carriers with mounted machine-guns, hundreds of members of he 63rd Parachute Brigade moved past fog-shrouded hills, as they fanned out in the southernmost tip of the zone. Entering at Presevo, they moved southward toward the villages of Noraca and Trvana,Accompanying the units was Lieut Gen. Nebojsa Pavkovic, the Yugoslav army chief of staff and Miloran Curic, a senior Defense Ministry official. Also traveling with the troops were NATO and European Union observers, sent to monitor terms of a cease-fire agreed to between Belgrade and ethnic Albanian militants.NATO helicopters clattered overhead as the vehicles rolled past tightly shuttered houses, while infantry fanned out across fields and forests.