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

More than 70 people remain hospitalized, with 24 of them in critical condition, according to Bangkok city officials.

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.

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.