US military helicopter crashes in Florida, all 11 troops missing

Eleven American troops are missing after a US military helicopter crashed in Florida during a training mission.

The Army UH-60 Black Hawk with four crew members and seven marines aboard went down during a night exercise at Eglin Air Force Base.

"Debris from the aircraft was located by search and rescue team at about 2 a.m. this morning. Search and rescue efforts are underway at the accident site currently," a statement from the US military said.

The identities of the missing people have not been released as their next of kin are yet to be informed of the accident.

The helicopter took off from an airport in Destin to join other aircraft during the manoeuvres but went missing shortly after its flight. A second aircraft which took a similar route returned safely and all members in the helicopter were accounted for.

The cause of the crash is yet to be ascertained. There was a travel advisory in place in the region warning of reduced visibility.