WASHINGTON — An American service member was killed by enemy fire in Afghanistan on Tuesday in the second United States combat death there so far this year.

A brief statement by the American-led military mission in Afghanistan said the incident was under investigation and provided no further details.

While it is unclear where the service member died, fighting has continued across the country. Taliban militants, American Special Operations troops and Afghan forces have been vying for territory as negotiations resume to end the 17-year war.

Hours after a massive attack on Monday that killed dozens of Afghans at an intelligence base in Wardak Province, a Taliban statement said the militants had resumed discussions with American diplomats in Qatar.