A Saudi Royal Air Force Hawk trainer jet. An investigation was opened into the cause of the crash of the British-manufactured Hawk. For illustrative purposes only. Image Credit: Courtesy: BAE Systems

Riyadh: A Saudi military trainer aircraft crashed on Monday while on a training mission, northwest of the kingdom, killing the crew, the defence ministry said on Tuesday.

An investigation was opened into the cause of Monday's crash of the British-manufactured Hawk, the ministry said in a statement carried by the official SPA news agency.

It provided no further details of the circumstances of the accident and did not specify how many crew were on board.