KABUL, Oct. 5 (Xinhua) -- A U.S. soldier has been killed following clashes in Afghanistan, the coalition forces said Friday.

"One U.S. service member assigned to the NATO Resolute Support (RS) mission was killed in Afghanistan on October 4," the U.S.-led NATO coalition or RS said in a statement.

"This incident is under investigation," the statement added.

Thursday's causality has brought to 11 the number of U.S. and NATO troops killed in Afghanistan so far this year.

Since Jan. 1, 2015, Afghan security forces have assumed the full security charges from NATO and U.S. forces.

Around 16,000 foreign troops remain in Afghanistan to train and assist local security forces in their fight against the insurgents.