WAR-CRIMES INVESTIGATORS FIND BONES IN BOSNIAN FIELD.

Byline: Associated Press 

Under the protection of U.S. troops, war-crimes investigators Wednesday found human remains and other evidence of a mass grave in a muddy field near Srebrenica.

Wearing plastic gloves and rubber boots, investigators from the U.N. tribunal used yellow markers for each of the 50 pieces of evidence, including a leg bone, part of a rib cage and a skeleton.

Wednesday was the first day of a mission to scrutinize seven locations in eastern Bosnia believed to contain the remains of Muslims killed last summer after the Srebrenica offensive.

But the mission is only one part of an attempt to gauge the full extent of killing in Bosnia. The arrival of spring in the first year of peace in the former Yugoslavia has thawed the ground around several hundred suspected mass-grave sites on all sides of the former front lines, and grisly secrets may come spilling forth.

The Sahinici field, about the size of a basketball court, is 18 miles northwest of Srebrenica, a demolished town where as many as 7,000 Muslims were believed to have been killed by Serb fighters in July in one of the Bosnian war's worst atrocities.

The site, which contained some brush and a pool of water, appeared to have been tampered with; mounds of muddy dirt rose from the ground. On one side of the site was a field of corn.

``We are collecting pieces of evidence,'' said Jean-Rene Ruez, one of six members of the investigative team. He did not elaborate on the findings, saying only that the dig would continue today.

``What you see are various bone fragments we have not disturbed,'' said John Gerns, a forensic scientist. ``We just photographed them.''

Gerns declined to answer questions about whether someone else had disturbed the site.

U.S. troops provided security, but for the most part remained out of sight of the field. There were fewer than 100 soldiers, but with Bradley fighting vehicles, artillery and attack helicopters.

Officials from the Yugoslav war crimes tribunal arrived in Bosnia on Monday to investigate at least seven suspected mass-grave sites stretching from Srebrenica to Zvornik on the Serbian border. The 2nd Brigade, 1st Armored Division, is providing security for the team.

Concerned about spreading itself too thin, NATO for months has resisted pressure to participate in the search for mass graves. But Washington appears to have ordered NATO to play a more active role.

Col. John Batiste of Jaffrey, N.H., commander of the 2nd Brigade, said he expected no trouble from the Serbs. The site was unguarded, though the field was marked off with yellow tape. No Serb military or police were seen in the area.

Batiste said he did not know how long the operation would last. He said the U.S. troops would clear mines, exhume remains and guard sites only when the investigators are actively working.

While some reports have concluded that Serbs tampered with the sites to cover up alleged war crimes, Batiste said the locations are under satellite surveillance, and he knew of no tampering.

The Christian Science Monitor reported Wednesday that two mass graves have been disturbed and the bodies of buried Muslims apparently removed in the area American forces have been assigned to safeguard.

The war crimes tribunal has indicted Bosnian Serb leader Radovan Karadzic and his military commander, Gen. Ratko Mladic, for their alleged roles in the Srebrenica massacres. Both are still at large.

Two Bosnian Serb soldiers also suspected of taking part have been extradited from Serbia to the tribunal.