A 10-year-old Chinese boy jumped 30 floors to his death after failing to write a self-criticism letter demanded by his teacher, state media reported.

The fifth-grade primary school student had been ordered to write a 1000-character apology by his teacher for talking during a test, Chines media reported.

The educator allegedly told him to jump out of a building after he failed to complete the task, the report quoted relatives and the neighbour as saying.

The boy is believed to have leapt to his death off a building where his school bag was found on the roof.

"Teacher, I can't do it,'' was found written in one of his textbooks, China National radio said.

"I flinched several times when I tried to jump from the building.''

The child, who lived with his grandparents, smashed into a parked car beneath the flat where his family live, the West China City News reported.

His furious relatives posted a banner outside the school in the southwestern city of Chengdu reading: "The teacher forced our kid to jump off the building,'' pictures showed.

"The police investigation is still under way,'' an official of Jinjiang district, where the incident happened, told AFP, declining to comment further.

Chinese media reported the head teacher as saying the boy was given two options: to write 1000 lines or stand for an hour, as punishment.

Strict discipline is an essential part of China's education system and culture, and tradition demands deference to authority, putting children under pressure to obey instructions.

The boy's school said on its verified account on Sina Weibo, a Chinese equivalent of Twitter, that the child and some of his classmates had been ordered to write reviews of their behaviour after they disturbed a speaking competition.

He died "by accident'', it said.

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