Supermarkets in Beijing have been instructed to stop selling knives after two random attacks left three people dead and three injured in the capital over the last week. The order by Beijing police, reported by the Beijing Times on Tuesday, comes a day after a city-wide crackdown on illegal weapons, which led to the seizure of 1,123 knives and 327 guns. Netizens have already ridiculed the move as ineffectual. "I can understand the police departments' concerns," social commentator Yao Bo wrote in a Sina Weibo post. "But what if someone goes into a supermarket and kills someone with a Durian?" Around January, shops received orders to require customers to register with their real names if they bought knives, customers noted online. Netizens have ridiculed the move as ineffectual. Beijing authorities have so far only on paper enforced provisional regulations requiring the registration of knives. These date back to 1983. The carrying of knives can be punished with adminstrative detention of up to 15 days and a fine of up to 200 yuan. The order comes less than 24 hours after a Beijing native, surnamed Wang, stabbed four people at Carrefour shopping centre in Beijing's western district around noon on Monday. Beijing police said that one of the four people wounded in the incident has died. As of Tuesday morning, a two-year-old boy was still fighting for his life at the Beijing Children's Hospital, Beijing Television reported. Wang had used a knife sold at the Carrefour shopping centre in his attack. He had been released from a Beijing mental hospital on January 11 after undergoing five months of treatment for an unspecified illness, police said. In a similar incident last Thursday, a 27-year-old man killed two people in the capital in a similar attack. The man later said he was mentally ill, according to police. Several cases of stabbings of schoolchildren have shocked the public over the last years. Most recently in May, a man described as mentally-ill was caught in a manhunt in Maoming, Guangdong province, after injuring six children and a women with a butcher's knife. China's first mental health law, which entered into force on April 30, was aimed at reforming the forcible detention of those mentally ill. The country has some of the highest rates of mental illness in the world, studies have shown . Knives were last banned in the capital during the 60-year anniversary celebrations of the founding of the People's Republic of China in October 2009, according to a Beijing News investigation. Police had denied the report at the time.