U.S. envoy Richard Holbrooke, trying to head off NATO intervention in the conflict over secessionist Kosovo, ended four days of diplomacy Friday saying he'd found no magic formula for peace.

Arriving in the southern Yugoslav province from a day of talks with Yugoslav President Slobodan Milosevic, Holbrooke met first with Adem Demaci, an Albanian who spent 28 years in Yugoslav jails for advocating Kosovo's independence.He then saw the Kosovo Albanians' main political leader, Ibrahim Rugova, before flying to Athens, Greece.

"I'm leaving this region today with no magic bullets for peace," Holbrooke told reporters.

He said he hopes that in the next two or three days, a diplomatic observer mission consisting of scores, or even hundreds, of foreigners will be going to Kosovo to see the fighting firsthand.

It was not clear whether that could serve as a prelude to NATO bombing the Serbian security forces if they refuse to withdraw.

Holbrooke noted only that "in the last two days, NATO has accelerated and concentrated their planning."

Holbrooke is pushing for at least some Serbian security forces to withdraw from Kosovo and for both the Serbs and Albanians to resume talks over the political future of the province, where ethnic Albanians outnumber Serbs nine to one.

Holbrooke reiterated late Thursday, after hours of closed talks with Milosevic, that no outside power wants an independent Kosovo.

"The international community will not recognize Kosovo as an independent country," Holbrooke said. "The international community is opposed to forcible change of boundaries."

Foreign powers fear the increasingly violent conflict in Kosovo could flare into a wider Balkan war.

More than 300 people have been killed since March, when Serbian police began a crackdown against militant separatists of the Kosovo Liberation Army, a shadowy group that emerged in 1996 and has recently gained ground among Kosovo Albanians weary of Serbian repression and Rugova's peaceful tactics.

The KLA now claims to control up to 40 percent of the rugged province. Road travel is increasingly dangerous, with KLA and police checkpoints blocking normal routes and daily gun battles waged for control of key arteries.