A panel of military officers plan to investigate a plane crash which occurred Wednesday night at Elmendorf Air Force Base near downtown Anchorage, Alaska.

Officials said the the C-17 cargo plane was on a local training run when it crashed with four crew members on board. All four are believed to be dead.

Witnesses said the crash sent a fireball rising hundreds of feet above the Alaska air base.

"It was a big, gray plume of smoke, and I saw a fireball go up in it," said Anchorage Fire Dept. Captain Bryan Grella.

Lt. Gen. Dana Atkins said the aircraft did not have an ejection and it was "likely nobody escaped."

"It's likely there are fatalities involved in this mishap," Atkins told reporters at a press conference.

The crash is the third airplane incident in Anchorage this summer.

Alaska Gov. Sean Parnell and Sen. Mark Begich issued statements expressing their sadness about the accident and also sent well-wishes to members of the military.

"Alaskans are very connected to the military, and our thoughts and prayers are with Alaska's Air Force family," Parnell said.