U.S. troops have arrested six Iraqis suspected in attacks against U.S. helicopters, including at least two allegedly involved in last week's downing of a Black Hawk (search) that killed all six Americans on board, officials said Friday.

U.S. troops captured the six during a series of nighttime raids between Tuesday and Friday in Tikrit, Saddam Hussein (search)'s hometown.

The military said the first two are suspected of involvement in the Nov. 7 downing of the Black Hawk in Tikrit. Lt. Col. Steven Russel, a battalion commander with the 4th Infantry Division (search), said the other four were involved in attacks against American helicopters but did specify which ones.

"We were targeting individuals believed to be involved in the shooting down of U.S. aircraft, helicopters," Russel told The Associated Press Television News.

One of those arrested was a police officer issued a badge by coalition forces, he said.

The Black Hawk went down near the eastern bank of the Tigris River. The U.S. military has not disclosed an official cause, but the commander of U.S. forces in Iraq, Lt. Gen. Ricardo Sanchez, has said he believes the helicopter was shot down.

"The people we've detained have some connection to the incident or we would not have gone after them," Russell said. "We still have some important leads we're trying to follow."

Iraqi police have also detained a number of suspects in the Black Hawk incident independently of the American efforts, U.S. officials said.

Hamid Muzhir, the police chief of Salahuddin province which includes Tikrit, said he believed the Black Hawk was shot down by members of Saddam's security forces because of the considerable training needed to launch such an attack.