The boy was stabbed on his way to school at about 8am on Wednesday by the suspected 44-year-old assailant, who was arrested on the spot, according to Chinese authorities. He died in the early hours of Thursday, Japanese foreign minister Yoko Kamikawa told reporters on Thursday.

“I take the incident extremely seriously,” Kamikawa said.

“This should never happen in any country. Particularly, I sincerely regret that this despicable act was committed against a child on his way to school.”

Japan has asked China to provide a detailed explanation of the facts and to take strong safety measures, she added.

The attack took place near the school on the anniversary of an incident in 1931 that triggered war between China and Japan, a sensitive date at a time when diplomatic relations are in danger of deteriorating.

It was the second such attack near a Japanese educational facility in China in recent months.

In June, a man attacked a bus used by a Japanese school in the eastern city of Suzhou, resulting in the death of a Chinese national who tried to shield a Japanese mother and her child from the assailant.

Also on Wednesday, a Chinese aircraft carrier entered Japan’s contiguous waters for the first time, the latest in a string of military manoeuvres that prompted a protest from Tokyo to Beijing.