BANGKOK — The death toll from a huge fire in a Bangkok music bar has increased to 30, officials said Tuesday.

More than 70 people were injured, with 24 of them still in critical condition, according to a statement by the Bangkok Metropolitan Administration.

The blaze at the Rong Beer Na Ladprao bar, the city’s deadliest in 17 years, broke out late Sunday in a northern part of the Thai capital. Firefighters needed half an hour to bring it under control.

The bar, which in Thai calls itself a brewery or beer hall, claimed to accommodate as many as 600 customers. It was not clear how many were present Sunday night.

An investigation into the cause of the fire and whether the bar was following safety regulations is ongoing. Most of the people who were killed were found trapped in windowless bathrooms where they may have sought to escape the flames, police said.

Bangkok Gov. Chadchart Sittipunt said Tuesday he has ordered the city’s administration to conduct a sweeping survey of such establishments to assess risks. The city will also step up enforcement of existing laws to improve safety standards, he said.

Former patrons of the bar and other mourners visited the site Tuesday, adding to the growing pile of flowers leaning on the guardrails cordoning off the location of the blaze.

Handwritten messages in Thai and other languages, including Korean, were left alongside white flowers, expressing condolences to the victims.

Debris from the bar — like melted musical instruments and blackened chairs — lay scattered along the sidewalk, moved there Monday by Thai officials investigating the cause of the fire.

University student Thanakon Phoklang said he was passing by and wanted to pay his respects, calling the loss regrettable.

On Monday, the president of the Thailand Structural Engineers Association, Amorn Pimanmas, told reporters outside the bar that, while he had not inspected the venue, he observed some risk factors that could worsen fire hazards.

He said the building is enclosed, has low ceilings and may have used foam as decorative materials, without adequate flame-retardant treatment. Combined with limited air ventilation, smoke would accumulate quickly, he said, creating toxic air that could be the main cause of death for many victims.

He also noted that officials said the bar was licensed as a restaurant with a live music venue rather than an entertainment venue because it was located outside the designated zoning for such businesses. Amorn said that would exclude it from the stricter fire safety requirements for entertainment venues.

“There must be some kind of revolution regarding fire safety procedures, and I think law enforcement is also very important,” he said. “It’s not that we don’t have the law, but it’s the problem of how the law could be strictly enforced from now on. I think the government should answer this question.”

____ This story has been corrected to show that 70 people were injured, not that 70 people remain hospitalized.