Two boys at a Tokyo juvenile medical reformatory have committed suicide, one in September and the other this month, the Justice Ministry said Tuesday.

One of the boys committed suicide Sept. 18 in his room at the reformatory in Fuchu, western Tokyo, by hanging himself with a towel from a coat hook, the ministry said.

The reformatory reduced the number of hooks in the rooms as a precaution, but another boy hanged himself on Feb. 14 with a piece of cloth attached to a bed frame. The boy left a suicide note, according to the ministry.

The boys were admitted to the medical reformatory with mental problems, but the ministry refused to reveal their ages or why they were institutionalized, citing privacy concerns. Their names have been withheld because they were minors.

There are four medical reformatories in Japan treating juvenile perpetrators of crimes who have mental problems. A boy committed suicide in November 2000 in one of the reformatories, located in Kyoto Prefecture.

Kazuo Kodama, security division chief at the ministry's Correction Bureau, said the ministry will instruct the reformatories to prevent further suicides.