A 21-year-old man who broke into a Chinese high school dormitory and stabbed nine boys to death has been executed less than two months after the attack.

Yan Yanming was put to death on Tuesday last week in the central province of Henan, where he was convicted of attacking the boys on November 25 in the city of Ruzhou, the official Xinhua News Agency said.

Yan’s mother turned him in to police after he attempted suicide the day after the attack, according to earlier reports. Xinhua said Yan confessed that he acted out of hatred.

The unusual speed with which the trial and execution were expedited suggests an attempt to reassure the public after a series of knife attacks at schools, which have left a total of 10 children dead and 42 people injured.

The earlier violence prompted the Chinese president, Hu Jintao, to issue a nationwide order in September for schools to hire guards and tighten security. It was not clear whether the new measures were in place at the school in Ruzhou.

The reason for the surge in knife attacks is unclear. They have taken place throughout China and involve attackers from different backgrounds.

But China’s cities and towns seethe with grudges and personal feuds amid dramatic economic and social change.

Fatal bombings, mass poisonings and other attacks are reported frequently, usually blamed on people trying to damage business rivals or seeking revenge in often minor disputes. Firearms are rarely used because private gun ownership is illegal in most parts of China.

Police said that Yan broke into the school dormitory at 11.45pm. The government-run China News Service cited a survivor who quoted him as saying, “Don’t blame me.”

Ruzhou, a city of 920,000 people, is about 450 miles south-west of Beijing.

Just before the attack, a court executed a man who slashed 25 children with a kitchen knife in September at a grade school in eastern China. Though no one was killed, a court ruled that the penalty was justified because the violence was “especially cruel”.

Police said that the attacker had a grudge against the parent of a pupil at the school.

In August, a man with a history of schizophrenia killed a student and slashed 14 children and three teachers at a Beijing kindergarten.

In September, a man armed with a knife, petrol and homemade explosives broke into a day-care centre in the eastern city of Suzhou and attacked 28 children before police stopped him. Police have not disclosed a possible motive.