Tokyo demands answers after fatal stabbing of Japanese boy in China

Beijing responded by expressing condolences for the killing, calling it an isolated incident that "could happen in any country".

While the motivation of the assailant remained unclear, Japanese officials have urged increased security around Japanese schools in China.

"For now, we will strongly urge China to provide an explanation about the facts of what happened. Since it's been more than a day since the incident happened, we expect them to offer an explanation as soon as possible," Prime Minister Fumio Kishida said, calling the attack "extremely despicable".

"A case like this must not be repeated. We will strongly call on China to ensure the safety of Japanese citizens and prevent a recurrence, while at the same time, doing everything doable in our capacity as the government," Kishida told reporters.

Police in Shenzhen said a man had attacked a minor on Wednesday morning and the child was rushed to hospital. The suspect, a 44-year-old man, was seized, they said.

Japanese media reported that the boy was a 10-year-old Japanese national living in the southern Chinese city, and was attacked near a Japanese school.

Beijing on Thursday expressed "regret and sadness" over the "unfortunate incident".

"We mourn the passing of the boy and express our condolences to his family," Chinese foreign ministry spokesman Lin Jian told a regular press conference.

Asked if the incident was isolated, Lin said that according to "the current understanding of the situation, this is an individual case".

"Similar cases could happen in any country," he told reporters.

Late Wednesday, before the boy died, Japan's Vice Foreign Minister Masataka Okano summoned Chinese Ambassador to Japan Wu Jianghao to convey "serious concerns" over the attack.

Okano "strongly urged that security be strengthened, including around Japanese schools throughout China", Japan's foreign ministry said.

'Isolated incident'

In June, a Japanese mother and child were injured in another knife attack in Suzhou near Shanghai, which China's foreign ministry described at the time as an "isolated incident".

A 55-year-old Chinese woman died attempting to stop the assailant and was honoured for her actions by the local government after her death.

It remained unclear if the latest incident was politically motivated.

It happened on the anniversary of the "Mukden incident" or "Manchurian incident" in 1931 in the lead-up to World War II.

An explosion on a railway was used by Japanese soldiers as a pretext to occupy the city of Mukden, now called Shenyang, and invade the wider region.

China's foreign ministry also did not comment when asked at a regular briefing about the significance of the date, which state media said was marked on Wednesday with air raid sirens in multiple cities.

Aircraft carrier

Relations have worsened in recent years as China takes a more assertive stance in territorial disputes in the region, and as Japan boosts security ties with the United States and its allies.

China last year banned Japanese seafood imports after Japan began releasing into the Pacific treated waste water from the stricken Fukushima nuclear plant.

After the release began, bricks and eggs were thrown at Japanese schools and consulates. Businesses in Japan were also inundated with nuisance calls from Chinese numbers.

A Chinese aircraft carrier this week sailed between two Japanese islands near Taiwan, the first such intrusion into Japanese contiguous waters, a zone within 24 nautical miles of its coast.

Government spokesman Hiroshi Moriya called the incident "totally unacceptable from the perspective of the security environment of Japan and the region".

"We have expressed our serious concerns to the Chinese side through diplomatic channels," he said.

China said the passage, which came less than a month after the first confirmed incursion into Japanese airspace by a Chinese surveillance aircraft, complied with international law.