Commissioner Thomas Hammarberg published his opinion after a fact-finding mission to Chechnya and Ingushetia in September.

He urged the Moscow-backed authorities to conduct "effective and independent investigations" into abductions, disappearances and unlawful killings of civilians and human-rights activists.

This summer, the murder of rights activist and journalist Natalia Estemirova in Chechnya provoked widespread outrage.

Concern over 'increased acitivity'

The North Caucus region is not yet stable, and "increased activity by illegal armed groups, the lack of effective investigations into disappearances and killings, and murders of human rights activists are of particular concern," Hammarberg wrote.

The report said public prosecutors estimated that more than 3,000 people had disappeared in Chechnya in the past nine years. It said Chechen authorities had discovered 60 mass graves containing 3,000 unidentified bodies.

Thorough investigations into past disappearances and identifying the dead bodies buried in the known sites in Chechnya should be carried out, it said.

"It is essential that the exhumation of corpses takes place in an orderly and methodological manner, demonstrating due sensitivity to the relatives concerned," the report said.

The commissioner, who served as the UN's regional adviser on human rights for the Caucasus region from 2001 to 2003, said he met with many families during his fact-finding mission whose relatives had disappeared.

Chechen officials estimate 3,704 people have gone missing since 2000.

Hammarberg said he recognized the need for the public to be protected from terrorism. But, he said, Russia should nonetheless insist human-rights safeguards are respected.

Clashes between Islamists, Russian authorities

"Human rights standards must be strictly applied in the detention of terrorist suspects during court proceedings," he wrote.

Russia's Caucasus region is facing an armed rebellion whose roots go back to the wars fought in Chechnya in the past decade. Deadly clashes between Islamist rebels and the Moscow-backed authorities are common in both Ingushetia and Chechnya.

jen/AFP/dpa
Editor: Nancy Isenson