The U.S. military says a Blackhawk helicopter has crashed inn an American base in Iraq, killing 1 service member and wounding 12 others.

The military says the helicopter went down Saturday night at the Balad Air Base, 50 miles (80 kilometers) north of Baghdad. It says the cause of the crash is unknown and under investigation.

The name of the service member killed is being withheld pending notification of next of kin.

With Saturday’s death, at least 4,345 members of the U.S. military have died in the Iraq war since it began in March 2003, according to an Associated Press count.

Balad Air Base is home to about 20,000 U.S. forces. It provides air power, logistics and counterterrorism support, as well as training for Iraqi security forces.