The blaze in the Yuhuatai district of Nanjing appears to have started on Friday on the residential building’s first floor, where electric bikes were stored, officials said at a press conference, citing the results of a preliminary investigation.
The fire was put out by about 6am and a search and rescue operation was wrapped up at about 2pm on Friday, authorities said.
Forty-four people were sent to hospital for treatment, according to authorities, with one person in a “critical condition”.
Twenty-five fire trucks were deployed to fight the blaze, emergency services said.
Footage shared on Chinese social media sites showed a skyscraper on fire at night, with black smoke emitting from the structure.