At least nine people have been confirmed dead after a fire engulfed a converted warehouse that was the site for a dance party in California’s Oakland on Saturday, Reuters reported. Around 35 people are reportedly missing, officials said, adding that the toll is expected to rise, The New York Times reported.

Officials said the fire at the artists’ collective, known as the Ghost Ship, in the predominantly blue-coloured neighbourhood started on Friday night, and that the cause was yet to be ascertained. Fire officials have described it as one of the worst fire incidents in the country’s history and speculated that several foreign nationals may be among the casualties.

Oakland authorities are investigating whether the two-story structure with two exits and “makeshift staircases” was in violation of the prescribed codes.

Mayor Libby Schaaf said, “This is complicated. And it’s going to take us time to do the investigation that these families deserve.” Around 12 people reportedly managed to escape while one person is undergoing treatment at a hospital.