BELGRADE, Serbia » Amnesty International denounced the United Nations administration in Kosovo for failing to investigate the widespread abduction and killings of Kosovo Serbs in the aftermath of the 1998-99 war.

The rights group said in a report released Tuesday that the U.N. mission in Kosovo had failed to deliver justice to the relatives of the victims, despite being charged by the U.N. Security Council with protecting human rights in Kosovo.

The U.N. assumed administration of the war-torn region after Serbia relinquished the control of most of Kosovo in 1999 when NATO chased its troops out of the region after a three-month bombing campaign that stopped a brutal crackdown against separatist Kosovo Albanians.

About 1,800 people went missing during the war that left some 10,000 dead, mostly ethnic Albanians.

Hundreds of Kosovo Serbs, who represent a minority in Kosovo, were abducted and most of them reportedly killed in revenge attacks by ethnic Albanian militants after NATO-led troops were deployed in the former Serbian province and the U.N. took over its administration.

The U.N. passed over most of its police and judicial responsibilities in Kosovo to an EU mission in 2008 after Kosovo declared independence from Serbia.

The report — a rare look at the plight of Serbs in Kosovo immediately after the conflict — listed several cases when the U.N. administrators allegedly failed to investigate atrocities against them. It was released on the eve of a U.N. Security Council debate on Kosovo on 29 August.

The U.N.’s "failure to investigate what constituted a widespread, as well as a systematic, attack on a civilian population and, potentially, crimes against humanity, has contributed to the climate of impunity prevailing in Kosovo," Sian Jones, Amnesty International’s expert on Kosovo, said in a statement.

Dragan Odalovic, whose son was among 14 Kosovo Serbs killed in an ambush on a field during a harvest in June 1999 in a Kosovo village of Gracko, said the U.N. police never caught the culprits.

"On that day up to now the U.N. police and others took my testimony some 50 or 60 times as I was the only witness," he said on Tuesday. "Nothing has ever been discovered so far by the U.N."

There was no immediate reaction from the U.N. to the report. But, the U.N. Interim Administration Mission in Kosovo, or UNMIK, said after previous such accusations that it had faced problems with the law and order because of widespread lawlessness in the wake of the war.

The Amnesty report said that for nearly a decade after the conflict, U.N. police and prosecutors "failed to initiate prompt, effective, independent, impartial and thorough investigations into many reports of enforced disappearances and abductions."

As a result, very few of those suspected of war crimes and crimes against humanity have been brought to justice in international or domestic courts, the report said.

Although the report focuses on the atrocities against Kosovo Serbs, Amnesty International said it has also conducted research which shows similar findings with regard to U.N. administration’s failure to investigate kidnappings of ethnic Albanians by Serb security forces.

"Years have passed and the fate of the majority of the missing on both sides of the conflict is still unresolved, with their families still waiting for justice," Jones said.

Associated Press videojournalist Sylejman Klokoqi contributed from Kosovo.