KHAN AL-RUBEA, Iraq (AP) - The knowledge weighed heavily on local Iraqis - the location of mass graves that witnesses say are filled with those who dared to defy Saddam Hussein's absolute power.

Human rights groups say Iraq is dotted with such graves. But before Saddam's government fell, citizens who knew or suspected were forbidden to go to the sites.

Now free to search for missing relatives, Iraqis on Saturday and Sunday dug up 72 bodies from a shallow mass grave 13 miles northwest of Najaf, one of Shiite Muslims' holiest cities. Bullet casings also were found in and near the graves.

Witnesses said the grave was filled with the bodies of men and women executed after a failed Shiite uprising against Saddam's regime in 1991.

''Everybody knew and could see, but they kept quiet,'' said Kamel al-Tamimi, a farmer. ''We were told to stay away from this area, not to go near it, that it was a security zone.''

Iraqis exhumed bodies with shovels and their bare hands, and they expected to find more remains this week. Others were searching the region around Najaf for additional mass grave sites in the area. At least one smaller site turned up a few miles away and was guarded by U.S. Marines.

''This is the tip of the iceberg in this country,'' said Marine Capt. Mike Urena. ''I am sure you will find more.''

More than 25 bodies were unearthed Saturday, and at least 10 had been identified, local Iraqis said. Another 47 sets of remains, including those of women, were uncovered Sunday afternoon. At least some of the victims were apparently lined up and shot.