Eight people, including two Boeing employees, were killed on Monday after a U.S. Air Force B-52 Stratofortress bomber crashed and burst into flames shortly after take-off from Edwards Air Force Base in Southern California.

“Today, Edwards Air Force Base experienced a terrible tragedy, and we lost eight great Americans,” a senior officer in the U.S. Army, James Hayes, said during a press briefing.

He described the victims as a “mixed crew of military, government civilians and government contractors”.

Mr Hayes said preliminary findings indicated that the crash was “tragic”, “not survivable”, and an “unrecoverable crash”. He disclosed that the military base has formed an interim safety board that would investigate the incident.

The base, situated northeast of Los Angeles, said the B-52 bomber took off at about 11:20 a.m. and was on a routine test mission when the incident occurred.

The chief master sergeant of the 412th Test Wing at Edwards Air Force Base, Joshua Skarloken, said efforts are ongoing to notify the families of the victims of their deaths.

“We extend our deepest condolences to the loved ones of the eight crew members who lost their lives in the B-52 crash at Edwards Air Force Base, California,” American Aerospace manufacturer Boeing Company said in a Facebook post on Tuesday.

“It is with great sadness that we confirm two Boeing employees were among those on board. We are in contact with their families and are offering support,” the company stated.