TAIPEI, Taiwan — Taiwanese President Ma Ying-jeou refused to accept the defense minister's resignation over an army recruit who died of heat stroke while being punished for bringing a cellphone on base.

Defense Minister Kao Hao-chu apologized Monday night for the death of Hung Chung-chiu on July 3 and offered to step down. Hung, 24, had been forced to perform a vigorous regime of sit-ups, push-ups, jumping jacks and squats in sweltering heat.

The military has punished 37 officers in connection with the incident, including 15 who face criminal prosecution.

Ma said Tuesday that a resignation by Kao was not justified under the circumstances.

Recruits are banned from bringing camera-equipped cell phones onto Taiwanese military bases for security reasons.

Hung was several days away from completing his 20-month military obligation when he died.

Taiwan is transitioning from a conscripted military force to an all-volunteer army. Its goal of completing the transition by 2015 appears unlikely from initial indications because of continuing difficulties in attracting requisite numbers of recruits.