The cause of the fire at the Mountain B nightclub in the Sattahip district of Chonburi province, about 160km (100 miles) southeast of Bangkok, in the early hours of Friday morning is under investigation, provincial police chief Major General Atthasit Kijjahan told PPTV television news.
He said the club’s owner and staff were giving statements at the police station and that a police forensic team would be collecting evidence at the scene.
Police said the fire was reported at about 12:45am local time (18:45 GMT).
Police also said that all of the victims so far have been identified as Thai nationals. A separate statement from the Chonburi emergency service described 14 of the injuries as severe.
Video circulating on social media showed people fleeing the club early on Friday morning while thick black smoke billowed from a doorway.
“The fire started at the top right corner of the stage,” a witness identified only as Nana told PPTV.
“The singer must have seen it too, so he shouted ‘fire’ and threw away the microphone.
“I am quite shocked. But I am lucky that when I saw the fire, I could get myself together and get out of there,” she said, adding that she saw several pub security guards with their clothing on fire.
“I shouted ‘fire’ to customers, and I was near the doors, so I directed them out. I kept shouting ‘fire, fire’ and the security guards were also helping lead people out,” she said.
The club was lined with flammable soundproofing, and it took two hours for firefighters to put out the blaze, Manop Theprith of a private emergency services group told the television station. His group said 40 people were injured.
The incident comes 13 years after pyrotechnics started a blaze at a New Year’s party at the crowded Santika nightclub in Bangkok, which killed 66 people and injured more than 200.
Investigations into that fire found several key safety breaches at the club and revealed lax attitudes towards safety at entertainment venues at the time.
Prime Minister Prayuth Chan-ocha on Friday assured families of victims that they would receive help from authorities and urged entertainment venues nationwide to ensure they have proper emergency exits and safety measures in place.