American service member killed in eastern Afghanistan

— -- An American Green Beret was killed in combat in eastern Afghanistan on Monday and four others were wounded in an area known for ISIS activity.

"Two wounded service members are being treated at a nearby medical treatment facility and are in stable condition," according to a statement released Tuesday by U.S. Forces Afghanistan. "The other service members have returned to duty."

The dead soldier was identified Wednesday as Sgt. 1st Class Mihail Golin, 34, of Fort Lee, New Jersey. The Department of Defense said Golin was killed "after being engaged by enemy small arms fire while on a dismounted patrol."

Golin was born in Riga, Latvia, and moved to the U.S. in 2004. He enlisted in the U.S. Army one year later.

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

Golin was an 18B Special Forces Weapons sergeant assigned to 10th Special Forces Group (Airborne). He had already completed three deployments to Iraq and Afghanistan and been awarded the Purple Heart.

The area around Achin, Afghanistan, has been a key battleground against the ISIS affiliate that operates in eastern Afghanistan. ISIS forces peaked at about 3,000 in 2016, but heavy fighting since then has dwindled their numbers to about 1,000.

Fifteen American service members died in Afghanistan in 2017. Almost half of that number resulted from anti-ISIS operations in eastern Afghanistan.

There are roughly 14,000 American troops in Afghanistan advising and assisting the Afghan military in the fight against the Taliban and ISIS.

New combat rules established by President Trump have allowed American troops to accompany Afghan forces at the battalion level, possibly placing them closer to combat situations.

ABC News' Elizabeth McLaughlin contributed to this report.