ISLAMABAD, May 20 (Xinhua) -- A training aircraft of the Pakistan Air Force crashed in Pakistan's eastern Punjab province on Wednesday, security sources said.

According to the security sources, the aircraft crashed during a routine operational training mission in Mianwali district of the province.

Both pilots ejected safely before the crash, and no casualties were reported on the ground, said the sources, adding that the incident happened due to some technical malfunction in the aircraft's engine.

An investigation into the incident has been launched.