By LAURA KING, Associated Press Writer

DEBELDE, Yugoslavia (AP) - On a steep mountain ridge a stone'sthrow from the Kosovo-Macedonian border, the lead man in a U.S.army patrol suddenly stops dead in his tracks.

``Fresh blood on the trail, sir,'' he calls back softly to thepatrol leader. They decide it's probably from an animal, buteveryone in the nine-man patrol casts a quick, wary look around.

Despite Macedonia's claims to have crushed a 7-week-oldinsurgency by ethnic Albanian guerrillas, American peacekeepersclosest to the conflict operate on the assumption that troublecould break out at any time.

Just across the frontier from this unit's territory isTanusevci, the ethnic Albanian village that was the flashpoint fora series of confrontations that began in February between therebels and Macedonian troops.

Macedonian troops backed by tanks, artillery and helicoptergunships launched an offensive against the rebels' borderstrongholds last week. Macedonia claimed victory; the insurgentssay they are simply regrouping elsewhere.

In Kosovo, a Serb province under U.N. administration, theNATO ( news - web sites)-led peacekeeping force has promised to help seal the border against infiltration and weapons-running into Macedonia by therebels, thought to use Kosovo as their prime staging ground.

Western nations have promised the Macedonians high-tech gear,including global positioning systems and remote-control equipmentfor defusing booby traps. But the real eyes and ears in the fieldare small, mobile foot patrols like this one.

On Thursday, a spring day that started out frosty and quicklyturned sweltering, a pair of American patrols stationed across adeep gorge from one another made a grueling trek to the bottom ofthe ravine and back up again - three hours of hiking on a narrowtrack that at times disappeared altogether, petering out into alayer of slippery leaves covering the steep hillside.

The two patrols met at the gorge's deepest point to swapsupplies and information. While they briefly conferred beside asmall stream, one soldier dropped to a prone position and sightedwith his rifle upstream - ``a potential avenue of hostileapproach,'' explained Sgt. Stan Millwood, 31.

The troops - members of Bravo Company of the 82nd Airborne's 1stBattalion 325th Infantry from Fort Bragg, N.C. - last came underfire in March, when they met a pair of guerrillas armed withassault rifles. The two rebels were wounded in the exchange of fireand treated at an American base hospital.

In a case like that - when the fighters are armed and on theattack - it is easy enough to identify the guerrillas. Otherwise,it can be hard to tell weapons-runners from local ethnic Albanianvillagers.

As the patrol made its way downhill, a pair of villagers passed,carrying rough farm implements and leading a horse with atraditional wooden saddle. The peacekeepers waved in greeting; theyknew them as farmers from the closest mountain hamlet, Debelde.

``We try to get to get so all the faces are familiar to us,''said Millwood. If the troops encounter strangers, they must quicklydecide whether to stop them, gauging factors like dress anddemeanor.

There was little extraneous chatter. The pace was brisk despiteup to 90 pounds of equipment on each man. They spread out information, scanned the opposite hillside for movement. Staying inradio contact with the squad on the opposite hill, theycommunicated with one another mainly by hand signals.

Conditions are Spartan in these two small outposts, the mostremote U.S. positions in Kosovo. The one closest to the Macedonianfrontier is an abandoned school, with framed crayon drawings by thekids still on the wall.

Nights are cold in the mountains, with only a wood-fired stovefor heat. There's no shower. One hot meal a day is flown in bychopper; the rest of the time the troops eat cold rations.

For many, this is a first deployment overseas, and the povertyof the ethnic Albanian villages is a shock.

``They're nice people - they've got hard lives,'' said 2nd Lt.Johnny L. David, of San Bernardino, Calif., who has been in Kosovofor three months.

The rebels' self-styled National Liberation Army enjoysconsiderable popular support in the mountain villages on both sidesof the border. In towns at the foot of the mountain, walls areemblazoned with the letters UCK - the movement's Albanian-languageinitials.

Dismissing the outposts' rough conditions, 1st Lt. Jeff Wilbur,23, of Annapolis, Md., said hot meals, bottled water and a roofwere luxuries for troops trained to live in the woods if necessary.

``It's a good adventure,'' he said.