Videos on social can be seen of patients climbing out of windows to escape the blaze.
At least 29 people have died in a fire at a Beijing hospital that forced the evacuation of dozens of patients, Chinese state media reported.
Staff removed 71 people after the fire broke out Tuesday in the inpatient department of Beijing Changfeng Hospital.
Videos of the fire circulating on social media show black smoke billowing from the building, with some people climbing out of the windows using what appears to be makeshift ropes made out of bedsheets.
Li Zongrong, deputy mayor of Beijing's Fengtai district, expressed his "deep condolences" as he announced the death toll at a press conference.
Twelve people, including the facility's director, have been detained in connection to the fire, said Beijing's public security bureau, adding that representatives from a company renovating the hospital were also being held.
State broadcaster CCTV reported that a preliminary probe revealed the blaze had been caused by "sparks generated during the internal renovation and construction of the inpatient department of the hospital".