A huge fire tore through a bar in Bangkok late on Sunday, killing at least 27 people and leaving eight critically injured.

The blaze started near the stage of the bar in the popular Chatuchak district, then spread rapidly, cutting power and engulfing the room with smoke, eyewitnesses say.

Footage posted online show panicked customers screaming as they fled – some with their clothes on fire – through the flame-enveloped front door of Rong Beer Na Lat Phrao.

Firefighters, who arrived at the scene just after midnight, quickly extinguished the fire. They found the bodies of most of the victims in a bathroom, where they had apparently sought shelter.

Preliminary investigations by Bangkok's disaster mitigation department suggest the fire could have been caused by an electrical short circuit in an air conditioner, though no official cause has been given.

Authorities have promised a thorough investigation.

This is not the first time such an incident has occured in Thailand.

Despite official promises to improve fire and electrical safety standards following previous incidents, they are still often poorly enforced.

Prime Minister Anutin Charnvirakul, who visited the scene early on Monday, said a musician who was performing when the fire broke out told him "there was blasting and everybody tried to flee from the smoke and flames".

Many people did not make it out of the bar because they "went to the back of the building and tried to hide themselves... in the toilet", the musician said, according to Anutin.

Firefighters, who were alerted to the blaze by a passing driver, were reportedly able to bring the flames under control in about half an hour.

However, despite their efforts, nine men and 18 women were killed, while more than 60 are now being treated in hospital, including eight who are suffering from critical injuries.

-BBC