MOSCOW (AP) — A gas explosion in an apartment building in the south-central Russian city of Novosibirsk Thursday morning killed three people, according to the latest reports from local authorities.

Novosibirsk is the administrative capital of Siberia and Russia’s third-largest city by population.

Regional Gov. Andrey Travnikov confirmed the deaths of three people, noting that two children were among a further nine people taken to the hospital. Two people were in intensive care.

“The nature of the injuries is varied — there are combined injuries, burns, and carbon monoxide poisoning,” Travnikov said.

The explosion caused two entrances of the five-story building to collapse, with 30 apartments destroyed by the ensuing fire. Eight people who may have been inside when the explosion occurred at 7:43 a.m. remain unaccounted-for.

A criminal case has been opened on the incident, which preliminary data suggests was caused by a gas leak. The Ministry of Housing and Public Utilities of the region said that the gas system of the building was checked in September 2022.