On the second day of her stay in Kosovo, Ms Arbour went to Celine, a village nine miles north-west of Prizren, where forensic investigators recently uncovered the bodies of 22 people - including 11 children - in a shallow grave.

The area was still littered by bedding, a child's pair of leather shoes and several shirts.

The BBC's Jeremy Cooke in Celine: "The stench of death is everywhere"

After visiting the site, Ms Arbour spoke of her determination to bring those involved to justice.

"Every grave that we uncover, every indictment that we bring, I think is an irreversible step [to prosecution].

"I do not know when this is going to happen, but there is no doubt in my mind that it will happen," she said.

Ms Arbour said the evidence collected in Celine would be added to hundreds of witness statements from Kosovo Albanians detailing atrocities allegedly committed by Serb forces in the province.

The 22 people found at Celine were believed to have been shot by Serb forces shortly after Nato began its bombing campaign against Yugoslavia.

Investigators believe the killings were part of a systematic sweep through the area - a traditional recruiting ground for the separatist Kosovo Liberation Army.

The BBC's Michael Voss on Ms Arbour's visit to one of the grimmest massacre sites in Kosovo

War crime indictments were issued on 27 May against Yugoslav President Slobodan Milosevic and four senior government and military leaders.

Ms Arbour has indicated that there may be sufficient grounds to extend these charges to include genocide.

The BBC's Michael Voss in Kosovo says the War Crimes Tribunal could also indict some of those believed to have been directly involved on the ground.

The Yugoslav authorities blocked attempts six months ago by Ms Arbour to visit Kosovo. At that time she wanted to investigate the massacre of at least 45 Kosovo Albanians in the village of Racak.

Protests against Russians

As Ms Arbour saw for herself the sites of alleged mass killings, Nato Supreme Commander General Wesley Clark went on a troubleshooting mission to the western town of Orahovac to urge Kosovo Albanians to have faith in Russian peacekeeping troops in the province.

The first elements of the main Russian contingent to the Kosovo peacekeeping force (K-For) are due to arrive over the next few days, but there have been repeated protests by Kosovo Albanians against the Russians' deployment.

The BBC's Jonathan Marcus: "The Russians are deeply distrusted by the Kosovo Albanians"

Orahovac, in the German-controlled sector of Kosovo, has seen almost daily protests against the 3,600 Russian troops, who Kosovo Albanians consider to be allies of the Serbs.

General Clark said the Albanian population "should be very confident" that the Russians "will follow the same rules of engagement" as the rest of the K-For peacekeepers.

The Nato commander also announced that the Dutch troops who were set to leave Orahovac once the Russians arrive will now stay.