One U.S. service member was killed and four more were wounded in Afghanistan on Monday following a "combat engagement," the U.S. said.

The attack took place in Achin, Nangarhar Province. Two of the wounded were treated nearby and are in stable condition, and two more have returned to duty, according to a release from U.S. Forces-Afghanistan.

"We are deeply saddened by the loss of one of our own,” said Gen. John Nicholson, commander of USFOR-A. "At this very difficult time our heartfelt sympathies go out to the families and friends of our fallen and wounded brothers."

Fifteen U.S. service members were killed in Afghanistan in 2017, according to icasualties.org.