LOS ANGELES, June 15 (Reuters) - A U.S. Air Force B-52 Stratofortress bomber crashed on Monday shortly after takeoff from Edwards Air Force Base in Southern California, and all eight crew members are presumed dead, the base said.

Edwards Air Force Base said in a statement released about four hours after the incident that the eight-engine aircraft, designed to carry nuclear and conventional bombs, was on a routine test mission when it crashed.

Aerial video footage of the crash site, about 161 kilometers north of Los Angeles, showed a burning, charred patch of land in the desert roughly the size of a football field, while an emergency services vehicle moved around the site.

No major wreckage appeared in the footage.

The base said on platform X, "A U.S. Air Force B-52 Stratofortress carrying eight people crashed today on a routine test mission shortly after takeoff... Initial indications suggest there was no possibility of survival."

She added that an emergency response team was on site and that officials were "working to identify all individuals." The Air Force said the cause of the crash was under investigation.

According to the Aircraft Accident Archive, a Geneva-based organization that compiles global aviation accident data, Monday's crash is the first of its kind for a B-52 Stratofortress since a similar aircraft crashed on Guam in May 2016. All seven crew members on board that aircraft survived.