Two U.S. Army soldiers were killed on Wednesday when an Apache military helicopter attached to Fort Hood base crashed into a field in Texas, igniting a large grass fire, according to officials.

Representatives from nearby Fort Hood confirmed the crash of the AH-64 Apache helicopter. Cliff Coleman, a spokesman for the Bell County Sheriff’s Office, verified the deaths of both occupants.

A military official told the Associated Press the helicopter was undergoing a routine training flight before it went down. The official spoke anonymously because the situation is still developing.

No cause of the crash was immediately announced. Fort Hood’s criminal investigation division was leading the crash investigation, Coleman said. The identities of the two soldiers are still being withheld pending notifications to their families.

“Today, an Apache helicopter crashed in Bell County during Fort Hood operations, killing two members of our military,” Texas Governor Greg Abbott said on X.

Fort Hood is a massive base with 214,968 acres (336 square miles) that is used to train and deploy heavy forces. The Army says the rolling, arid terrain around the base provides an ideal training ground.

In November 2015, four soldiers were killed when a Black Hawk helicopter crashed during a training exercise. And nine Fort Hood soldiers died in 2016 when a rain-swollen creek swept their vehicle into rushing waters.

The helicopter did not hit any homes or other structures when it crashed, Coleman said.

“You could tell it was a violent crash,” Coleman said. Photographs from the scene showed firefighters walking around a charred field as plumes of dark smoke rose from flames still burning in the wreckage.

“Our immediate priority is securing the site and supporting the initial response efforts,” said Brig. Gen. Ethan Diven, acting commanding general. “Our thoughts are with the crew and their families as we await further information.”

The AH-64 Apache attack helicopter has been a key part of the military’s fleet since the first versions were deployed in 1984. The Apache crew sits behind each other with the pilot in the rear and the co-pilot gunner in the front position.