Saudi Arabia’s Ministry of Defense said that one of its fighter jets crashed during a training mission on Thursday, killing all the soldiers onboard, Report informs via Al Arabiya.

The ministry’s spokesman, Brig. Gen. Turki al-Maliki, said the accident involving an F-15 fighter jet happened during a routine training flight at the King Abdulaziz Air Base in Dhahran.

An investigation has been opened to determine what caused the crash.

In a similar incident in July, a Saudi F-15 crashed during a training mission in Khamis Mushait, killing all members of crew onboard.