US Service Member Killed in Afghanistan He was killed by a roadside bomb.

 -- A U.S. military service member was killed in eastern Afghanistan today during a joint U.S.-Afghan counter-terrorism operation targeting ISIS in Afghanistan. The service member died from injuries resulting from the blast of an improvised explosive device.

The service member, who has not been identified, was killed during operations in the Achin District of Nangarhar Province in eastern Afghanistan, according to a statement from Resolute Support, the coalition training mission in Afghanistan.

"The service member was killed conducting operations with Afghan forces when the patrol triggered an Improvised Explosive Device," said the statement. "The mission was conducted as part of a larger United States-Afghan counter-terrorism mission targeting the Islamic State, Khorasan. An investigation is being conducted to determine the exact circumstances of the event."

"On behalf of all of U.S. Forces - Afghanistan, we are heartbroken by this loss and we extend our deepest sympathies to the families and friends of the service member," said General John W. Nicholson, commander of USFOR-A. "Despite this tragic event, we remain committed to defeating the terrorists of the Islamic State, Khorasan Province and helping our Afghan partners defend their nation."

Last year, former Taliban groups in eastern Afghanistan re-branded themselves as ISIS and were believed to number as many as 3,000 fighters.

That move led the White House to authorize airstrikes and counter-terrorism missions against the group that over the past year have whittled their numbers down to 1,000 fighters.

The U.S. maintains 9,800 troops in Afghanistan as part of the Resolute Support training mission to help the Afghan military fight the Taliban.