F-16 jet crashes in Nevada, pilot's condition unknown
This US Department of Defense photo shows an F-16 Fighting Falcon aircraft as it flies over the Pacific Alaskan Range Complex on October 16, 2008 (AFP Photo/Jonathan Synder)

A U.S. Air Force F-16 jet crashed at Nellis Air Force base in Nevada on Wednesday, the third crash involving a military aircraft in the past two days.

The condition of the pilot was not known and emergency responders were on the scene, the Air Force said in a statement.

 It added that the jet crashed during routine training earlier on Wednesday.

On Tuesday, a U.S. Marine Corps helicopter crashed during a training mission in Southern California. All four crew members are believed to have been killed.

Another Marine jet crashed in Djibouti on Tuesday. The pilot was in stable condition.

Reporting by Idrees Ali; Editing by Peter Cooney