TAIPEI • An unsupervised Taiwanese naval officer who accidentally fired a missile towards China while experimenting with a missile launcher was one of three men charged yesterday over the incident.

The supersonic "aircraft carrier killer" that was mistakenly fired last month struck a damaging blow to the military's image, embarrassed President Tsai Ing-wen and angered Beijing.

The Hsiung-feng III missile hit a Taiwanese trawler, resulting in the death of the skipper and injured three other crew members.

The accidental firing - the biggest military slip-up since Beijing-sceptic Ms Tsai came to power in May - sparked an uproar in Taiwan and drew a stern rebuke from China.

Prosecutors in the southern port city of Kaoshiung yesterday said naval officer Kao Chia-chun was left alone in the master control room for as long as seven minutes.

Kao decided to practise without a supervisor, despite the system being in "combat mode", the prosecutors said in a statement marking the end of their investigation.

"He did not ultimately notice that missiles No. 3 and No. 4 were already in 'live-fire' mode and went on to press... 'allow launch', 'launch missile', and 'confirm'," prosecutors said.

One of the missiles was airborne for about two minutes, and was automatically searching for a target before locking onto the fishing boat in the waters off Taiwan-administered Penghu island.

Kao was charged with negligence leading to death and injuries, as well as damaging weaponry.

His supervisor Chen Ming-hsiu and Lieutenant Hsu Po-wei, who was responsible for overseeing weapons, were charged with neglecting official public duties, which then led to the catastrophe.

Chen should have been supervising but left Kao alone during the incident on July 1, the statement said.

President Tsai last week called for the Defence Ministry to hammer out a new strategy and improve its performance, while attending an annual military exercise that simulates China attacks.

The mainland is the biggest military threat to self-ruling Taiwan, which Beijing sees as a breakaway province that will be reunified.

The misfire incident coincided with China's celebrations to mark the 95th anniversary of the founding the ruling Chinese Communist Party.

AGENCE FRANCE-PRESSE