Russian and American troops stood side by side along the main drag of this eastern Kosovo town, allies in exasperation.

On the southern edge of town, a crowd of ethnic Albanians blocked the road. Five hundred yards farther north, a crowd of Serbs blocked the road. Five hundred yards still farther, another crowd of ethnic Albanians blocked the road. And after another 500 yards, yet another crowd of Serbs blocked the road--at the northern edge of town.

The standoff last week was triggered by the discovery of two murdered Serbs by the roadside, victims of a campaign of terror that is driving Serbs from Kosovo, a province of Serbia, the dominant republic in Yugoslavia. Because of the latest killings, outraged Serbs here in Kosovska Kamenica blocked the main road through town at two points. That prompted Albanians, who claimed a busload of their kin had been kidnapped, to do the same.

In an almost comical pas de deux, U.S. and Russian troops tried to clear the road. American Humvees passed through ethnic Albanian roadblocks, but the crowd refused to allow Russian peacekeepers to pass. The Russians passed through the Serbian roadblocks, but the Serbs then closed ranks and refused to allow Americans to pass.

The ethnic Albanians chanted "USA!" and shouted "Russians out!" as a pressing crowd forced a Russian vehicle to back away from them. The Serbs screamed obscenities at an American helicopter, which blew the tiles off some of their roofs as it circled overhead.

"Look at American democracy!" shouted one Serbian man. "It brings murder!"

"The Russians are looting our apartments!" shouted an ethnic Albanian man.

Invisible to the warring roadblockers, however, was the cooperation between American and Russian troops, who stood together and consulted about how to defuse the situation despite different and frequently hostile Kosovo policies advocated by their governments in Washington and Moscow.

About 2,000 Russian troops are now stationed in Kosovo, a number that will rise to 3,600, and they find themselves cast as protectors of the Serbian side of the ethnic divide. They are a mirror image of the NATO troops, who are cast as protectors of the ethnic Albanians.

Russian and NATO officers alike say they are eager to dispel that impression. But since Russian troops unexpectedly seized the Pristina airport on June 11, a full day before chagrined NATO troops arrived in the province, the Russians' role here has been particularly controversial. Sometimes it is more than controversial; it can be dangerous. Russian soldiers at several checkpoints were fired upon on Thursday and Friday, and one was wounded.

Serbs, who greeted the Russians as liberators, see them as historic allies and protectors. Ethnic Albanians--in a rare meeting of minds--concur. The Russians beg to differ with both.

"Russians didn't come here to make a war, but the villages where our troops patrol don't understand that," said Maj. Konstantin Konovalenko, an officer stationed at Pristina airport. "We came here to provide peace. . . . We are neutral, not for Serbs, not for Albanians."

About 500 Russians are now patrolling around Kosovska Kamenica, an area 25 miles east of Pristina, the provincial capital, that has a significant and increasingly isolated Serbian population. When they arrived in early July, the Russians held joint patrols with U.S. troops, but two weeks ago they began working alone, although they still intersect with U.S. forces.

Vladimir Grigoriev, a soldier with an elite Russian airborne division, likes to think of himself as a romantic and of Kosovo as a kind of adventure. "I volunteered for Kosovo," said the 26-year-old from a town on the Volga River, who is on his first foreign assignment. "I wanted to see people, the world."

As Grigoriev moves by foot through the nearby Serbian village of Donje Korminje, peacekeeping can seem like a pleasant enough calling. Villagers emerge from their homes to smile and wave. Children follow on bicycles, some offering the three-finger Serbian salute. He doesn't return the gesture.

The affection Grigoriev and other Russian troops receive as they patrol Serbian strongholds in the American peacekeeping sector of Kosovo is in sharp contrast with the scowls and suspicion they encounter when they enter ethnic Albanian enclaves. And the efforts of American troops to smooth a path for the Russians there in recent weeks have failed.

"We see Russians as occupiers, not peacekeepers," said Beqir Cana, 35, an ethnic Albanian from the village of Koretin.

And residents of Koretin charge that the Russians have been harassing local Albanians. According to Anton Ramadani, 22, and his 21-year-old brother, Afrim, Russian soldiers, wearing black masks and speaking Serbian, verbally abused them at a checkpoint here and demanded that they give them the three-finger Serbian salute. The Ramadanis and two other men suggested that masked Serbs may also have been manning the checkpoint with the Russians.

A spokesman in Pristina for the multinational peacekeeping force said there are no indications that Russian units operate checkpoints differently from soldiers of other countries. And Brig. Gen. John Craddock, head of U.S. forces here, said the Russians have been working effectively.

This, despite the Russians' low-tech, shoestring operation. On a recent night, the floodlit British compound beside Pristina airport was alive with the sound of singing from partying British troops. Next door, Russian guards huddled in a candlelit post, some pop music crackling from a small radio. Soldiers outside moved through a darkness lit by cigarettes, heading for their bleak headquarters.

"We are culturally different people," said one Russian officer. "We don't need [luxury] to accomplish our mission."

Russian soldiers said they only wish to be seen as professionals. "We want to build peace," said Andrew Ivanov, 25, who also served as a U.N. peacekeeper in Croatia. "We want to let people work, to let people raise their children."

But the goal of a multi-ethnic Kosovo is looking increasingly elusive. A convoy of farm tractors carrying 440 Serbs from villages near here with a U.S. escort passed Russian soldiers, who watched silently as they filed by. "It seems there is nothing we can do for them," said Konovalenko. Nearly 75 percent of the prewar Serbian population of 200,000 has fled Kosovo for other parts of Serbia since NATO bombing in early June ended and NATO-led peacekeepers took over.

For one senior Russian officer, who asked not to be identified, the area he patrols is turning into bandit country. "Shooting every night," he said with regret. As he looked at hills in the distance, the vista summoned distant memories:

"This looks like Afghanistan," he said.

CAPTION: Russian peacekeepers form a roadblock in Kosovska Kamenica to separate ethnic Albanians from Serbs. Ethnic Albanians have accused the Russians of harassing them.

CAPTION: French soldiers subdue a demonstrating ethnic Albanian in the latest outbreak of violence in the mining town of Kosovska Mitrovica. At least four were arrested and three injured in the protest, which lasted several hours. See story, Page A27.