Three other people were in a state of cardiopulmonary arrest, public broadcaster NHK reported -- one at the mall and two others at a factory in Yatsushiro city where a smokestack collapsed. Advertisement AdvertisementAdvertisement AdvertisementThe mall blast was likely caused by a gas leak, a government source told the Kyodo news agency. After nightfall, regional officials said 10 people were unaccounted for at the mall, NHK reported. No immediate abnormalities were recorded at nuclear power plants, the Nuclear Regulation Authority said. About 45,000 households and facilities had no power in the Kumamoto region, according to local utility Kyushu Electric Power.