KHAKERAN VALLEY, Afghanistan —  Skimming low over the desert in helicopters with guns at the ready, American troops advanced into the Khakeran Valley (search) in southern Afghanistan, three months after Taliban (search) rebels attacked police and forced them to flee.

The move is the latest part of a strategy to reassert U.S.-led coalition and Afghan control over an insurgent stronghold, after a spate of attacks raised fears of an Iraq-style insurgency here. Blistering U.S. assaults against nearby mountainous rebel camps last week left 178 suspected militants dead.

Up to 300 insurgents are suspected to be in the Khakeran Valley, about 130 miles northeast of the main southern city of Kandahar (search), said Lt. Luke Langer, a platoon leader in the 503rd Infantry Regiment, 173rd Airborne Brigade.

"The enemy has been using the Khakeran Valley as a sanctuary," he said Sunday. "Without question, I know the Taliban are in the area and I'm sure we will make contact. From talking to local people, we know the enemy are very angry with us being here."

Flying in a convoy of two CH-47 Chinook helicopters, a Blackhawk and two Apache attack choppers, about 50 American troops hopped up the river valley from village to village in search of the rebels.

At the first hamlet, the soldiers rushed from the aircraft as a handful of mangy chickens scampered away in clouds of billowing dust. A few farmers stood around and watched with nervous, but curious, looks on their faces as the troops searched the few mud huts and fields of wheat and tomatoes that made up their community. Nothing suspicious was found.