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.


Fire in rebel-held east Congo kills 24 schoolchildren
Trump touts $5,000 payout if Republicans win as Vance waits in wings
Search expands after Philippine ferry fire kills five and leaves dozens missing
Trump says Iran war to end after US midterm elections
At least 20 killed in cargo vessel fire at China shipyard, state media reports
US military says it struck vessel in Caribbean, killing 3
At least 14 killed in explosion at weapons depot in Syria
US hits five Iranian oil tankers after attack on Navy ships
