"A United States Air Force B-52 Stratofortress crashed shortly after takeoff on the Edwards airfield at 11:20 am," the base, located about 60 miles (95 kilometers) north of Los Angeles, said on Facebook.

"Emergency crews immediately responded to the scene and the situation is ongoing."

There were no immediate details about casualties, and a spokesman from the base declined to give any further information.

Aerial footage showed a huge charred area on the ground.

There appeared to be very little left of the plane, with the journalist in the broadcast helicopter speaking of a "large plume" of black smoke that had been visible in the aftermath of the crash.

A number of emergency vehicles could be seen by the burned patch.

The B-52 is a long-range bomber that has been used by the US Air Force since the 1950s.

With a combat range of up to 8,800 miles the plane is capable of carrying a nuclear payload.

The United States has deployed the aircraft in conflicts in Vietnam, the Gulf, Iraq, Afghanistan and most recently in Iran.