BAGHDAD, Iraq (CNN) -- Four people with possible ties to last May's ambush and kidnapping of American soldiers were captured southwest of Baghdad, the U.S. military said.
An Iraqi family waits on the ground during a raid on their village Friday by U.S. and Iraqi troops.
Helicopters carried about 600 U.S. and Iraqi troops Friday to two Sunni villages -- Owesap and Betra -- 15 miles southwest of Baghdad to take on militants, Multi-National Division Center spokesman Lt. Col. Randy Martin said.
The four detainees are being questioned about "possible ties to the missing, captured soldiers," he said.
Martin said the military believes al Qaeda in Iraq has been staging attacks from the area and has links to the May 12 ambush near Mahmoudiya, which is south of Baghdad.
Four American soldiers and an Iraqi interpreter were killed in the May attack, and three U.S. soldiers were kidnapped. The body of one was found later, and two other soldiers are still missing.
Friday's raid was intended to begin establishing a "sustained coalition presence" in the region, Martin said.
A military statement said U.S. soldiers from the 3rd Brigade Combat Team, 101st Airborne Division, and 150 Iraqi soldiers were transported in four waves by two CH-47 Chinooks and eight UH-60 Black Hawks.
Marines and U.S. soldiers helped secure the landing zone and 70 "concerned local citizens" helped secure the outlying perimeter. Troops moved through villages and started building a bridge across the Euphrates River.
Before the air assault, U.S. F-16 fighter jets dropped two 2,000-pound bombs on a Euphrates island thought to be used by al Qaeda for staging attacks.