WASHINGTON — A U.S. service member was killed in Afghanistan’s Nangarhar Province on Tuesday while carrying out operations against Islamic State, the U.S. military said in a statement.

“The service member was killed conducting operations with Afghan forces when the patrol triggered an Improvised Explosive Device,” the statement said.

Islamic State has attracted hundreds, perhaps thousands, of fighters in Afghanistan and Pakistan to join its ranks, and holds some territory in Nangarhar. But it has not been able to expand its influence in Afghanistan beyond a few districts and the Taliban remain the dominant militant force.

Pentagon spokesman Peter Cook told reporters in Washington that an investigation was under way and he was not aware of any other casualties in the incident.

Thousands of U.S. troops remain in Afghanistan, with many recent airstrikes and special operations missions aimed at Islamic State in Nangarhar, but they have also been helping Afghan forces fight Taliban elsewhere in the country.

According to Pentagon data, 1,832 U.S. service members have been killed in action in Afghanistan since 2001, when U.S.-led forces invaded the country and toppled the Taliban regime.