An Iranian US-made F-5 fighter plane crashed Sunday after hitting a mountain in the west of the country, killing both crew members, Iranian media reported.

The two pilots were killed upon impact as the jet fighter hit the mountain near Abdanan town of Ilam province, town governor Morad Naseri was quoted as saying.

Naseri said the crash was being investigated by authorities.

Iran's air force retains an aging fleet, including US-manufactured aircraft purchased before the 1979 Islamic revolution.

In January 2012, a US-built F-14 fighter crashed minutes after takeoff, also killing both crew.