Baghdad, Iraq ? U.S. troops and Iraqi police backed by tanks, artillery and aircraft on Tuesday hunted down paramilitary groups loyal to Saddam Hussein along the Tigris River about 50 miles north of Baghdad in one of the largest U.S. military operations since the fall of Saddam’s regime.

There was no information on casualties on either side.

A statement from U.S. Central Command, which oversees the U.S. occupation of Iraq, said 397 suspects and “numerous weapons systems and ammunition” had been seized since Operation Peninsula Strike began early Monday.

The operation on a peninsula of the Tigris River northeast of the city of Balad appeared to signal a determined effort by the U.S. military to stamp out attacks by suspected Saddam loyalists that have undermined reconstruction efforts and claimed the lives of 11 U.S. soldiers in Iraq in the past two weeks.

The latest attack occurred on Tuesday when two assailants fired rocket-propelled grenades at paratroopers from the 82nd Airborne Division manning a weapons collection point in southwest Baghdad.

Central Command said one paratrooper was killed and a second was in critical condition.

Central Command said Operation Peninsula Strike was aimed at “eradicating Baath Party loyalists, paramilitary groups and other subversive elements.”

Because the operation was continuing, Central Command withheld the number of U.S. troops and Iraqi police involved, the name of the peninsula where the operation was taking place and the U.S. units involved.