The death toll from a devastating fire at a music bar in Bangkok has risen to 30, while more than 70 people remain hospitalized, Thai authorities said on Tuesday.

According to Bangkok city officials, 24 of the injured are in critical condition following the blaze, which broke out late Sunday at the Rong Beer Na Ladprao bar in the northern part of the Thai capital.

Firefighters brought the fire under control after about 30 minutes, but the incident has become Bangkok's deadliest fire in nearly two decades.

The venue, which describes itself as a brewery or beer hall, has a capacity of around 600 patrons, although authorities have not confirmed how many people were inside when the fire started.

Police said many of the victims were found trapped inside windowless bathrooms, where they had apparently sought shelter from the flames.

Authorities have launched an investigation into the cause of the fire and whether the establishment complied with safety regulations.

On Tuesday, former customers, relatives and other mourners gathered at the site to pay tribute to the victims, leaving flowers and handwritten condolence messages in Thai and several other languages, including Korean.

Burned musical instruments, charred chairs and other debris from the bar remained scattered around the area after being removed by investigators examining the scene.