Fresh evidence suggests that most, if not all, of the Kuwaitis who disappeared after Iraq invaded its oil-rich neighbor in August 1990 were killed, U.N. Secretary-General Kofi Annan (searchsaid in a report Tuesday.

"After many years of maneuvering and denial by the previous government of Iraq, a grim truth is unveiling itself," he said. "The discovery of mass graves in Iraq containing the mortal remains of Kuwaitis is a gruesome and devastating development."

The Kuwaiti government (searchhas stepped up efforts to identify some 605 of its citizens who disappeared after the Iraqi invasion.

Until its ouster in April, Saddam Hussein's regime insisted it had released all prisoners taken from Kuwait during the occupation and the subsequent 1991 Gulf War (searchthat liberated the country. It refused to cooperate with Kuwaiti and international efforts to find the missing prisoners.

No prisoners have been found alive since the U.S.-led war in Iraq earlier this year and Kuwaiti hopes that any will be discovered have diminished.

While holding out hope that some of the missing Kuwaitis could be found alive, Annan said prospects are dim.

His report included evidence of atrocities committed by Saddam's regime including photographs of mass graves and human remains.

Annan called for justice for the victims.

"The removal from Kuwait of civilians — men and women — their execution in cold blood in remote sites in Iraq, and a decade-long cover-up of the truth constitute a grave violation of human rights and international humanitarian law," he said.

"Those responsible for these horrendous crimes, particularly those who ordered the executions, must be brought to justice," Annan said.