At least six people are considered missing and could still be in the rubble following a major fire that raged through a historic building in Old Montreal on Thursday morning, emergency officials said at a news conference Saturday. 

Investigators had initially said one person was believed to be missing after the fire.

Montreal fire operations chief Martin Guilbault said information recently confirmed from various sources led them to conclude more people were trapped inside when the fire broke out before 6 a.m. Thursday.

Nine people, three of whom had serious injuries, were transported to the hospital Thursday. As of Saturday, two are still receiving treatment in the burn unit.

Police said Saturday the case had been transferred to the Montreal police arson squad as of Friday night. 

Steve Belzil, commander of the arson squad, said he could not provide any information about the identities of these people, including whether or not they were residents of the building or people who had rented a space there on Airbnb, for example.

Firefighters have yet to be able to safely enter the three-storey building at the intersection of Place d’Youville and Saint-Nicolas Street in order to investigate.

Authorities therefore are not able to determine the cause of the fire, but at this time, there is no talk of arson.

„[The case] has been transferred [to the police’s arson department] because we have reason to believe that there are victims, deaths,” explained Belzil.

This weekend, specialists will help the fire department prepare how they can enter the building to investigate the fire’s origins and look for anyone who is still missing „while trying to preserve the heritage building,” said Guilbault.

Emergency officials say it may take several days or even weeks to determine the cause of the fire. 

In a tweet, Alain Vaillancourt, Montreal’s executive committee member responsible for public security, said these are „extremely trying times” and his heart goes out to the families of those that are missing.