MANILA: Two Philippine air force planes collided during a training flight and crashed at an air base south of Manila, killing all four pilots onboard, Philippine officials said Saturday.

The two SF-260 aircraft collided while flying at a low altitude Friday afternoon then crashed at Fernando Air Base in Lipa city in the coastal province of Batangas south of the capital. There were no injuries on the ground, the officials said.

The air force did not provide details of what it called an accidental crash. Two Philippine officials with knowledge of what happened said the two planes collided in flight. The officials spoke on condition of anonymity because they were not authorised to discuss the matter.

One of the two-seater aircraft went down near the barracks of military personnel in the air base, a witness told The Associated Press.

The air force said it has temporarily grounded all its remaining SF-260s, which were acquired from Italy, as an investigation takes place. It did not say how many SF-260s were left in the air force.

The accident was a setback to the underfunded Philippine military.

It has long struggled to modernise its air force, navy and army due to financial constraints while dealing with decades-long communist and Muslim insurgencies and increasingly hostile territorial disputes with Beijing in the South China Sea.