Fire swept through a 14-storey Ratchathewi apartment building on Soi Phetchaburi 18 in Bangkok early on Tuesday, killing at least three people and injuring about 30.
One of the victims survived the fire but succumbed at hospital.
Police said many people were inside the building during the fire. Around 30 were sent to hospital to be treated for smoke inhalation.
Firemen on the scene said they believed the fire started at about 2.30am in an electric wiring duct on the fifth floor. It sent smoke billowing throughout the building, which has about 100 units.
Firefighters said they managed to put out the blaze and would continue to ventilate the building to get rid of the smoke and heat that had built up and threatened those trapped inside.
Petchaburi Road was closed between Pratunam and Ratchathewi intersections.
