A woman was killed and 12 other people injured after a man carried out a knife attack in a mall in a busy shopping district in the Chinese capital, Beijing, police said on Sunday.

Beijing police said in a short statement they had detained a man over the early afternoon attack at the Joy City Mall in the Xidan district.

Three men and 10 women were sent to hospital after the attack and one woman died of her injuries, police said. The others were all expected to recover.

The man had already confessed to carrying out the attack to “express his discontent”, they said but did not elaborate.

Beijing radio showed pictures on their WeChat account of blood spattered on the floor in part of the mall and at least one injured person being taken from the scene.

Violent crime is rare in China compared with many other countries, especially in major cities where security is tight, but there has been a series of knife and axe attacks in recent years, many targeting children.

In 2015, police arrested a sword-wielding man who killed a Chinese woman and injured a French man in Beijing’s fashionable Sanlitun shopping and entertainment district.

Such attacks are often blamed on people with mental illness or who have personal grievances. Knives are most commonly used because gun controls are extremely strict in China.

However, the government has also blamed some knife attacks on militants from the violence-prone far western region of Xinjiang, where Beijing says it faces an Islamist insurgency, adding to China’s nervousness about such incidents.

Thirty-one people were killed in 2014 during a knife attack at Kunming train station in southwestern China that the government said was the work of Xinjiang militants. Police shot dead four of the attackers.

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