The U.S. military has found an estimated 1,500 unmarked graves in this northern Iraqi city, though it remained uncertain whose remains they contain.

U.S. military officials on Thursday surveyed the site near a military base and industrial park on the southern edge of the city. Members of the Patriotic Union of Kurdistan — one of two main political groupings in the northern Kurdish autonomous region — reportedly exhumed one body.

The graves, marked only by weeds and little mounds of dirt, are in neat rows stretching several hundred yards across a parched landscape.

Although little is know about the site, suspicion immediately fell on ousted Iraqi leader Saddam Hussein's campaigns of war and repression.

Tens of thousands of Kurdish men disappeared in Iraq during Saddam's rule — part of a drive to crush an independence movement and drive ethnic minorities from oil-rich areas.

Human rights groups say Saddam's government abducted and murdered them.

After a Kurdish autonomous region was established in northern Iraq in 1991 under the protection of the United States, human rights investigators said they found numerous mass graves in areas that had fallen from Saddam's grasp.

The oil city of Kirkuk was not part of the autonomous region, and its capture during the war to oust Saddam was considered a great prize for the Kurds.

Officials have yet to begin a formal investigation of the graves.

"I'm a scientist by training," said David Downing, a U.S. civil affairs official brought to the site by journalists. "I'll wait for the scientific results to come in before I make any conclusions."

Downing said forensics teams would first have to gauge the layout of the site before digging up remains for examination.

A Kurdish Iraqi soldier based near the site in 1987 said nighttime caravans often brought bodies to the site.

Residents of a nearby residential district said the bodies of unidentified Iraqi soldiers who died in the 1991 U.S.-led Gulf War were buried there.

"After 1991 it became larger and larger," said Ramadan Qazi, a worker at a nearby soft drink plant.

Earlier this month, British forces in southern Iraq found about 200 boxes containing human remains in a warehouse near the city of Zubayr and are still investigating how they got there.