The U.S. military in Afghanistan says three of its service members were killed and three others wounded when an improvised explosive device exploded near the troubled central eastern city of Ghazni.

An American contractor was also wounded in the blast.

A brief statement issued in Kabul said, “The wounded service members and contractor were evacuated and are receiving medical care.”

It did not share further details.

Tuesday’s fatalities bring to 11 the number of American soldiers killed in action in Afghanistan this year.