A fire that ripped through a hospital in Fukuoka as patients slept early yesterday killed 10 people - eight of them elderly patients - and prompted government demands for safety reviews.
The blaze left a further five people injured, four seriously.
Video footage showed firefighters surrounding the hospital in Fukuoka, in the southwest, as smoke poured from the front entrance of the partially gutted building. Dark streaks of soot were smeared across the second floor windows.
"We have confirmed the deaths of 10 people - eight inpatients and two hospital workers," said a local police spokesman. The workers were a former hospital director and his wife.
"We did our best in fire fighting to save lives ... but it was a difficult situation," a fire station official said.
"We received news of the fire at a very late stage, and there had been no attempt by staff to tackle the fire in its early stages.
"Patients on the second and third floors were exposed to a lot of smoke because fire doors that would have stemmed the flow had been left open."
"We first received the report of a fire after a nurse who was inside the hospital rushed out and asked a taxi driver to make an emergency call," he added.
Local media reported the fire may have started at a treatment room that had a laser device and thermal therapy equipment that used a water boiler.
Hours after the tragedy, Japan's fire and disaster management agency issued administrative guidance to fire headquarters nationwide that officials check hospitals to ensure medical organisations are prepared for nighttime fires.
It also sent seven officials to the scene to probe the disaster.
A 43-year-old woman living in the neighbourhood told the broadcaster NHK: "A lot of smoke came to the front door of my house and I heard shouts like 'Help!' and crunching sounds."
A man who lives in the neighbourhood told another broadcaster, Nippon TV, that the ground floor "was red with flames and was filled with smoke. The part where beds were located seemed to be burning".
Fukuoka has many narrow streets, which could have hampered access.