At least 27 people were killed and 22 left in critical condition when an explosive fire swept through a popular pub in Thailand’s capital late on Sunday (July 12), officials said, in one of the deadliest such incidents in Bangkok in recent years.

The blaze broke out at 11:57 p.m. at the Na Ladprao pub in Bangkok’s Chatuchak district and was brought under control roughly half an hour later. “We have recovered 27 bodies, others are being sent to hospital,” Prime Minister Anutin Charnvirakul said after visiting the scene. Based on survivor accounts, he said the venue rapidly filled with smoke, forcing many patrons to run to the back near the bathrooms — where there were no fire escapes.

A total of 63 injured people were hospitalised, according to Suriyachai Rawiwan, director of the Bangkok Metropolitan Administration’s Department of Disaster Prevention and Mitigation. Of those, 22 remain in critical condition, Bangkok Governor Chadchart Sittipunt told reporters.

A musician performing at the pub told the prime minister he saw smoke coming from a circuit breaker near the stage before the power cut out and an explosion followed, with thick smoke quickly engulfing the room. “The fire was not that aggressive, but the smoke had engulfed 100% of the venue,” said firefighter Chakrit Khongkom, 45, who arrived on the first truck. “Most of the survivors were choking on smoke.”

Rescue workers found many victims lying near the pub’s toilets, where they had apparently sought shelter from the flames. The cause of the fire remains under investigation. “We have to wait for the police to investigate,” Suriyachai said.

Update (July 14): The confirmed death toll from the blaze has risen to 30, and Thai police say they are investigating whether negligence caused the disaster. Police General Kittiratt Phanphet said the use of flammable materials as stage decoration — which may have accelerated the fire’s spread — “indicates a lack of caution and disregard for the safety of the patrons.” Preliminary findings suggest the fire began with a short circuit in an air-conditioning unit that cut power throughout the venue. A fire-safety expert who inspected the Rong Beer Na Lat Phrao premises found the door near the restrooms — where many victims were found — had been locked, while the two entrance doors were partially blocked by furniture. Survivors described the bar as dimly lit with poorly marked exits. As of Tuesday morning, 27 of the dead had been identified; more than 70 people were injured, 24 of them critically.