A U.S. soldier was shot and killed by unidentified assailants at a checkpoint in western Iraq, a military statement said Monday.

An undetermined number of attackers pulled up late Sunday to the roadblock near the Syrian border and requested medical help for a person in the car. They then pulled pistols and shot the soldier, a statement released by the U.S. Central Command (search) said.

Troops returned fire, killing one person and capturing a second. At least one other assailant fled in the vehicle.

The soldier's name was not released pending notification of his family.

The killing appeared to be part of an escalation of clashes between American troops and Iraqis in the central and western regions of the country. Dozens of soldiers and Iraqis have been killed or wounded in daily skirmishes.

A U.S. patrol in the troubled city of Fallujah (searchcame under fire from a mosque Monday. Soldiers did not return fire but arrested two suspects, Centcom said.

Fallujah, a Sunni Muslim stronghold about 30 miles west of Baghdad, has been the scene of almost constant clashes since U.S. troops shot dead 18 demonstrators and wounded 78 others in two confrontations in April. Residents have accused U.S. troops of regularly using excessive force and of not respecting Islamic practices.