All seven military personnel aboard a U.S. Air Force HH-60 Pave Hawk helicopter were killed Thursday in a crash in western Iraq near the Syrian border, U.S. defense officials told Fox News.

It’s the first deadly aviation crash for the U.S. military in the war against ISIS in Iraq and Syria since American involvement began in 2014. But U.S. Central Command said in a statement the crash “does not appear to be a result of enemy activity.”

“This incident is under investigation,” the statement said. The Pave Hawk is a modified version of the Black Hawk helicopter.

“This tragedy reminds us of the risks our men and women face every day in service of our nations,” said Brig. Gen. Jonathan P. Braga, director of operations, Combined Joint Task Force-Operation Inherent Resolve. “We are thinking of the loved ones of these service members today.” – Fox News

There have been reports suggesting the helicopter hit a power line.

Featured image of an HH-60 Pave Hawk helicopter landing as an Army UH-60 Blackhawk prepares to pick up a medivac patient June 13. The 33rd Expeditionary Rescue Squadron is the first squadron to have a combat-search-and-rescue mission and a medevac mission, and is based at Kandahar, Afghanistan. U.S. Air Force photo/Senior Airman Brian Ferguson.