An Air Force B-52 Stratofortress bomber crashed shortly after takeoff at Edwards Air Force Base in California on Monday, the base said.

“Emergency crews immediately responded to the scene and the situation is ongoing,” the base said in a statement.

The crash was reported at about 11:20 a.m. local time.

The base has closed the airfield and said all inbound planes are being diverted.

The Air Force and NASA conduct test flights of new and developmental aircraft at Edwards Air Force Base.

The B-52 Stratofortress — which typically carries a crew of five — is a long-range bomber first introduced in the 1950s that remains a central part of the U.S. military’s air power. Built by Boeing, the aircraft is capable of carrying both conventional and nuclear weapons over long distances and has been used in conflicts ranging from Vietnam to operations in the Iran war.

This is a developing story. Please check back for updates.