A Bosnian Serb accused of orchestrating atrocities against Muslims and Croats at three prison camps went on trial Monday in the Yugoslav war crimes tribunal's first genocide case.

Milan Kovacevic, 57, is charged with genocide, war crimes and crimes against humanity for his role in atrocities committed around Prijedor in northwest Bosnia in 1992.He has pleaded not guilty to all 15 charges. If convicted, he faces a maximum life sentence.

His trial, the U.N. court's seventh, will publicize alleged atrocities in three of Bosnia's most infamous prison camps: Omarska, Keraterm and Trnopolje.

In her opening arguments, prosecutor Brenda Hollis said camp guards "were free to kill, torture and rape."

"In Omarska, people saw corpses every day . . . killings were routine in Keraterm," she said.

There were so many dead bodies at Omarska that large trucks were needed at times to remove them from the camp, Hollis said.

Hollis said Kovacevic, an anesthesiologist, was among municipal officials who engineered a violent campaign to expel Bosnian Muslims and Croats from Prijedor between April and December 1992.

Kovacevic was vice president of a group that ordered attacks on non-Serb villages, the seizure and detention of Bosnian Muslims and Croats, and the establishment of prison camps.

Prosecutors say the alleged atrocities began with heavy artillery attacks on non-Serb villages. Some of those who survived the attacks were executed. Others were rounded up and taken to one of the camps.