A teenage girl jumped to her death from a residential high-rise yesterday morning, after being reprimanded by a teacher for taking other student's cell phone.

The girl, who had her schoolbag with her, climbed over the rail on top of the 20-story high-rise in the Shanghai Greentown in the Pudong New Area shortly before 8am.

She went back and forth over the rail several times, hesitating for five minutes before jumping, a witness said.

Shocked residents who witnessed the tragedy paid tribute to the girl online.

A microblogger identified as "Zhimajiang," living across from the building, said he called police when he saw the girl on the roof. But she jumped before rescuers could arrive, and he was shocked and saddened to see her fall.

The girl was a grade eight student in nearby Jianping Xiangmei Middle School, where it is said she took another student's cell phone.

Her class teacher talked with her parents about the incident and asked her to write a confession letter last week.

School officials said she behaved normally afterwards, attending school on Monday.

An Anhui Province native, the girl came to the school about a year ago.

This incident has once more put the spotlight on the psychological fragility of teenagers. Eight city students killed themselves last year, two more than 2009.

The cause of yesterday's apparent suicide is still under investigation by the authorities.

"The cell phone incident may have been a trigger," said Zhang Qi, deputy director at the East China Normal University's psychological counseling center.

"As a newcomer, she needed to integrate into the new environment and find new friends," he said.

Qi's remarks were echoed by Yang Yongming, a Shanghai Education Commission official in charge of child safety.

"If she could have talked about her unhappiness with her parents, teachers and peers, she might have eliminated her unhappy emotions and the tragedy could have been avoided," Yang said.