A fire broke out at an office building under construction in Tokyo's western suburbs on Thursday, killing at least four people and injuring about 40 others, many seriously, authorities said. Another person was feared trapped inside the building.
More than 70 ambulances and fire engines were sent to the site.
Fire officials said more than 20 people were seriously injured, including some with burns to their respiratory tracts. Tokyo metropolitan police said four people were confirmed dead.
The three-story building in Tama city, which also has three underground floors, was near completion. About 300 workers were at the site at the time of the fire.
Television video showed dozens of people in khaki work clothes and helmets taking refuge in a nearby parking lot. Rescue workers were searching for one person who might be trapped in the building.
The cause of the fire and the extent of the damage were being investigated, the fire department said. Kyodo News service said the fire was believed to have started in construction materials on the bottom basement floor during steel cutting work.
Fires at construction sites in Japan are not rare.
In Tokyo alone, 100 to 200 fires are reported annually at buildings being built, repaired or renovated, according to the fire department. Welding work, arson, and smoking by construction workers are among the main causes.