TOKYO -- Japanese police said Friday that the number of deaths in a wave of student suicides had risen to five, despite appeals to bullied or troubled youngsters to resist the temptation to take their own life.


A 14-year-old schoolboy hanged himself and a 13-year-old boy jumped in front of a moving train Thursday in Saitama prefecture, north of Tokyo, adding to a string of youth suicides which have shocked Japan.


The deaths came only hours after a group of psychiatrists issued a statement urging students not to copy three bullying victims who committed suicide over the past three weeks.


The deaths, widely covered in the media, have triggered national soul-searching about bullying in Japan's tightly-disciplined school system and the victimization of children who somehow stand out from the crowd.


But local police quoted teachers, parents and classmates of the two latest suicides as saying they could not think of any reason for their action. The 13-year-old boy left no suicide note, but the other student said in his note, "This is an experiment to find out what will happen to me after death.


"Although television programmes reported a string of suicides as a result of bullying, mine is a mere experiment. I would never kill myself because of bullying," the note said.


The student's father told police his son had been reading a book explaining ways of committing suicide.


"It is a critical situation," Hiroshi Inamura, a psychiatry professor at Hitotsubashi University, said. "It looks like the beginning of copycat suicides among students who are not involved in bullying or have any serious problem."


Inamura, one of the psychiatrists who issued the statement, said the situation reminded him of a wave of suicides triggered by the suicide of a popular singer in 1986.


"Teenagers tend to beautify and yearn for death, and massive media coverage of student suicides easily prompts them to follow suit," Inamura said.


"The best way to stop copycat suicides is for the media to stop covering them. If that is impossible, then they should report such news as calmly and simply as possible."


The case which first drew media attention was that of Kiyoteru Okouchi, 13, who hanged himself leaving a note which said classmates repeatedly dunked him in a nearby river and extorted more than $10,000 from him over a year.


The shockwaves from the suicide spread as far as the government, prompting Prime Minister Tomiichi Murayama to hold a special cabinet meeting to discuss schoolyard bullying.


Following the meeting, the Education Ministry issued a directive urging teachers to crack down on bullying.


The National Police Agency said six bullying victims committed suicide this year, up from three last year.


From January to October this year, police investigated 66 cases of criminal bullying, involving such crimes as assault and extortion, up from 56 in the same period last year.


They said that a total of 231 students were involved in such offenses against 117 victims during the period, up from 155 offenders and 77 victims last year.


Forty-four percent of the bullies said they had tormented classmates because they were "weak and nonresistant," while 24 percent said the victims "acted like a teacher's pet."