U.S. Marines are moving into a Taliban-held town in southern Afghanistan in the first major American operation in the region in years.

Several hundred Marines are pushing into the town of Garmser, an area classified as Taliban territory.

U.S. commanders say the Taliban have been expecting an assault on the town and that militants have been setting up improvised explosive devices.

The commanders say they didn't know how much Taliban resistance the Marines would face when they entered the town before sunrise Tuesday.