The death toll from a fire at a psychiatry clinic in western Japan rose to 24 on Friday, according to local media.
The fire broke out in the clinic on the fourth floor of an eight-story building in Osaka city, Kyodo News reported.
Firefighters and ambulances were dispatched to the scene in the Kitashinchi district to extinguish the fire that started at around 10.20 a.m. (0120GMT).
Citing the fire department, the report said 17 men and 10 women, all showing no signs of life, were brought out from the building.
Later, 24 people aged between 20 and 60 were confirmed dead apparently due to carbon monoxide poisoning, according to police, it said.
Describing the deadly incident as "tragic," Prime Minister Kishida Fumio said in a statement that they will take all necessary measures to prevent such incidents from happening again.
Police said they had intelligence that the fire was caused by some liquid leaking from a paper bag held by a man who appeared to be in his 60s and that it could be arson.