A woman was killed and a dozen people were injured in a knife attack at a busy shopping mall in Beijing on Sunday, amid tighter security ahead of the Lunar New Year holiday. The woman died in hospital after emergency treatment, the Beijing Public Security Bureau said in a statement. Three men and nine women were still being treated in hospital, none of them for life-threatening injuries. A 35-year-old suspect from Henan province, identified only by his surname Zhu, was arrested at the scene and has been detained. Police said the man had carried out the attack because of a “personal grievance”, without elaborating. The attack took place at the Joy City Mall in Xidan – one of the Chinese capital’s busiest shopping areas located about 2.5km (1.5 miles) from Tiananmen Square – at around 1pm. Eight killed in Xinjiang knife attack: police shoot three attackers No further details were given, but by late afternoon, all shops and restaurants at the mall were open as usual except for The Dining Room on the fourth floor which had been sealed off, its windows covered in blue tarpaulins and a police officer standing guard at the entrance. A waitress at a noodle restaurant on the third floor told the South China Morning Post she heard screaming but did not know what had happened. “I heard screams but had no idea what was going on – it was just chaos,” she said. “The area upstairs [on the fourth floor] was quickly cordoned off and we only found out about the attack online afterwards.” A Joy City employee also said the scene was chaotic as people ran for the exits. Staff members shut down the escalator between the third and fourth floors and pulled down the roller doors on shops and the restaurant on the fourth floor. A video posted on microblogging platform Weibo, apparently filmed by a diner in a restaurant, shows a knife-wielding man rushing towards a customer eating lunch with two men who throw chairs and cups at him until he flees. Another video shows people running to get out of the mall past what appears to be trails of blood on the floor. A group of police officers armed with weapons used to subdue terror suspects are also seen at the mall in another video posted on Weibo. Roads around the mall were briefly blocked off, according to some online accounts that included photos of ambulances and police cars waiting outside. Another photo posted online shows several customers sheltering in a store behind a locked door. It is unclear whether all of the 12 people being treated in hospital were injured by the suspect or when they were rushing to escape. Police did not immediately respond to an inquiry from the Post . The attack happened five days before the Lunar New Year, the most important holiday for Chinese people that falls on Friday. Security has been stepped up across the city and on public transport, including the subway, railway stations and airports, as tens of millions of people travel home for the holiday. Police officers and dogs have been deployed to patrol Beijing’s three railway stations since Friday, according to The Beijing News . During a video conference on Tuesday, Minister of Public Security Zhao Kezhi urged police around the country to be vigilant before and during the festival to maintain social stability.