The fire broke out around 1 a.m. at Mountain B nightclub, a one-story building in Sattahip district, Chonburi province, southeast of Bangkok. and about 30 kilometers (18 miles) south of Pattaya city, a popular tourist destination, Thai police said.
Police Colonel Wuttipong Somjai told CNN the fire happened during a music concert and the burns ranged from “mild to severe”.
All of those who died were Thai nationals, he confirmed. Rescue officials said one of those dead was a 17-year-old, the youngest death identified to date.
Colonel Somjai said investigations into the cause of the fire were ongoing.
Nattanit Pikulkaew said she was at the nightclub to celebrate her brother’s birthday and was near the front of the stage when a woman ran in screaming that the roof was on fire.
Seconds later, she saw that the speakers on stage were on fire.
“In no time, the fire spread to the ceiling,” she told CNN, adding that when members of the public tried to flee, the entrance to the club became blocked.
“I saw people trying to break the glass walls but they were too thick,” she said.
Her brother suffered severe burns and is in critical condition; his friend died inside the building.
Raphon Namtham, a local musician who regularly performs at the nightclub on Monday nights, told CNN the venue opened two months ago and has become popular with locals for its live band performances, which take place every evenings from 12 p.m. to 1 a.m. “Customers come to drink and dance,” he said.
He was not at the nightclub when the fire broke out, but said the front door was the only point of entry and exit for patrons.
Musicians entered and left through the back door, which would be locked during performances, he said.
He added that the nightclub’s ceiling was lined with highly flammable acoustic panels.
Namtham said the band Taew Waew were performing at the time of the fire and their replacement singer and keyboardist were among those who had died. He said the drummer was on life support at a nearby hospital.
Photos taken by local search operation Rescue Sattahip showed badly charred seats inside the venue.