WASHINGTON — An American service member was killed Tuesday in Afghanistan, the first combat casualty there since January, the military announced.

The attack on a patrol with a roadside bomb occurred in Helmand province where Taliban forces have been gaining ground against Afghan government security forces. The U.S.-led NATO coalition bolstering Afghan troops have scrambled in recent days to keep them from losing Helmand province, the restive area home to many Taliban members.

Another U.S. service member and six Afghan troops were also wounded in the attack.

About 100 U.S. special operations forces were sent there Monday to train and advise Afghan forces who were struggling to control the provincial capital of Lashkar Gah.