KABUL (Reuters) – Three U.S. service members were killed and three wounded when an improvised explosive device detonated on Tuesday near the central Afghan city of Ghazni, the NATO-led Resolute Support mission said in a statement.

A U.S. civilian contractor was also wounded in the blast and was receiving treatment with the other wounded, the statement said, giving no further details.

The deaths are the latest in a growing toll on U.S. forces in Afghanistan following the death of an army Ranger following an operation against al Qaeda militants in Nimruz province on Saturday. Resolute Support said the soldier had been accidentally shot by a member of Afghan partner forces.

There was no word on the circumstances of the blast but Ghazni has been one of the most heavily fought over areas of Afghanistan this year.

The city was overrun by a large Taliban force earlier this year before being driven off by Afghan and U.S. forces after days of heavy fighting.