Three people were killed and 15 others injured in a knife attack at a suburban supermarket in Shanghai on Monday on the eve of China’s week-long National Day holiday, the latest in a series of stabbing incidents in major Chinese cities this year.

The assailant, a 37-year-old man surnamed Lin, has been detained, local police of Songjiang district said in a statement on Tuesday.

According to an initial investigation by police, Lin had travelled to Shanghai to vent his anger following a personal financial dispute.

The knife attack came one day before China’s National Day “Golden Week”, when holiday travel was expected to surge.

Public stabbing incidents have risen over the years in China, with authorities often putting the blame on mental illness. Children at schools are a common target.

In September, a 10-year-old Japanese student was fatally stabbed by an attacker metres from his school in the southern Chinese city of Shenzhen.

That incident along with a June knife attack on two Japanese nationals in Suzhou, a major city in eastern China have stoked security concerns among members of the Japanese community in China.

Stabbing incidents are rare in Shanghai but not unprecedented.

In 2022, a man went on a stabbing spree at a major hospital in the Chinese financial hub, injuring 15 people.

The man, whom authorities said was “resentful of society” after an investment fell through, was sentenced to death a year later.