TAIPEI : A Taiwanese fighter jet crashed on Friday morning during an exercise, killing its two pilots.

The aircraft crashed within the grounds of a military base in Hukou, some 50 kilometres south of the capital Taipei.

Two visiting Singaporean military personnel were also killed, and two others have been hospitalised.

The twin-seat fighter jet crashed after completing a simulated low-altitude attack.

According to the Taiwanese Defence Ministry, the flight was part of the island's annual Hankuang military exercise.

Eyewitnesses say the F-5F aircraft failed to pull up in time, and crashed into a military base in Hukou.

One says: "I was with my children in the park when we saw the jet flying just above us. The jet flipped twice and crashed."

Two visiting Singaporean soldiers who were in a storeroom at the base were killed.

Nine other Singaporeans were injured, two of them seriously.

They were there in support of the Singapore Armed Forces' unilateral training in Taiwan.

Lee Jye, Taiwanese Defence Minister, says: "Their casualties included two men who were killed and two who were injured."

The two soldiers who suffered severe burns were rushed to a military hospital in Taipei's Neihu district.

Doctors say one of them, a 22-year-old, is in critical condition.

He had burns on 50 percent of his body, and also suffered from smoke inhalation.

The second man suffered burns on 40 percent of his body.

Doctor Chen Tien Mu, Surgical Department, Tri-service General Hospital, says: "The one with more serious injuries couldn't speak much but the other man had requested to call his mother. He didn't say anything about the situation then."

According to doctors, both men suffered from second to third degree burns on their head, shoulders and back.

They are now undergoing intensive care at the hospital's burns centre and doctors are desperately trying to stabilise their condition.

The Taiwanese Defence Ministry has grounded all its F-5F fighters pending the outcome of an investigation into the accident.

This is the second crash involving an F-5F jet fighter in a year.

Last June, an F-5F crashed into a rice field during a training flight, killing a pilot and injuring the other pilot.

Taiwan has about 60 ageing F-5 jets, and it is trying to replace them with newer fighter aircraft. - CNA/ch