At least four people at a renowned Shanghai hospital were wounded by a knife-wielding assailant on Saturday.
It's the second reported stabbing incident after a COVID-19 lockdown of the financial hub was lifted early in June.
Officers raced to the more than 100-year-old Ruijin Hospital on Saturday morning after receiving calls about an attack, police said.
Videos on social media showed chaos as visitors clambered under turnstiles to get out of the hospital while doctors were seen running out with their patients, some in wheelchairs and one on a mobile bed.
Hospitals are a flashpoint for many in China, who face issues from touts illegally trading appointment tickets, long queues to see doctors, and corruption that can push up the cost of receiving care.
Reports of patients assaulting doctors are also common.
At the Shanghai hospital, police found a man holding a crowd hostage with a knife on the seventh floor of the outpatient department. When the man threatened to hurt the hostages, the police opened fire, subduing him, according to local police.
None of the wounded is in a life-threatening situation and the incident is being investigated, the police said.
Ruijin Hospital has been cordoned off, and all appointments cancelled, a police officer told onlookers outside.
A man was arrested on Monday after going on a stabbing spree in the city's downtown Jingan district.


No evidence alleged Bondi gunmen received military training in Philippines
At least 12 killed in Nigeria mining site attack
Russian attack on Ukraine's central Cherkasy injures six, causes blackouts
UN, aid groups warn Gaza operations at risk from Israel impediments
Israel approves natural gas deal with Egypt, Netanyahu says
US approves $11.1 billion largest-ever arms package for Taiwan
Trump adds seven countries to full travel ban list
Indian parliament votes to allow private firms in nuclear power sector
