A U.S. Army Apache attack helicopter has crashed off the coast of La Porte, Texas, killing the two soldiers on board.

According to KXAN, the Texas Army National Guard reports the helicopter crash occurred just before 4 P.M. Yesterday, Dec. 28th. The two soldiers were on a routine training flight when they crashed unexpectedly.

Eyewitnesses report that the aircraft flew unusually low, and there was a loud noise before the helicopter broke apart in mid-air.

By the time first responders arrived on the scene, much of the helicopter had already become submerged. Rescue divers worked into the early hours trying to recover the bodies of the fallen soldiers. The two soldiers’ remains were retrieved from Galveston Bay early this morning.

The helicopter crashed in the Houston Ship Channel, after taking off from Ellington Field Joint Reserve Base. Pieces of the fallen aircraft were also identified at the Bayport Cruise Terminal near the site of the crash.

The reason for the crash is still uncertain, and investigations remain ongoing.