Manila/IBNS, Oct. 24 -- Four pilots were killed after two military aircraft collided mid-air during a training session at an air base in the Philippines on Friday, media reports said.

The Philippine Air Force confirmed on Saturday that the two SF-260 single-propeller aircraft crashed at Fernando Air Base, south of Manila.

An investigation has been launched to determine the cause of the mid-air collision.

As a precautionary measure, the Philippine Air Force has grounded its fleet of SF-260 aircraft following the incident.

In May this year, two pilots were killed when another SF-260 aircraft crashed during a training session in Benguet province in the northern Philippines.

The latest incident has renewed attention on the safety of mili...