Multiple people are dead after a crane attached to a high-rise building under construction collapsed in downtown Kelowna, British Columbia, on Monday, police said.

“There are multiple confirmed fatalities and we are working to confirm all occupants and workers of the building and the worksite,” said Inspector Adam MacIntosh of the Kelowna RCMP detachment, according to Global News.

“The crane fell to the north, striking the adjacent professional business building, causing damage. The crane also fell across the rear parkway, striking the roof to an old-age home,” he added.

Police would not say if the victims are workers or bystanders, stating that not all next of kin have been notified yet.

One person not connected to the worksite remains unaccounted for, MacIntosh said.

The Mission Group, a residential and commercial real estate developer, said the “catastrophic failure” occurred during the crane dismantling process.

“Mission Group expresses its deepest sympathy for the families of those affected by this tragedy,” the company said in a written statement. “We have set up support services to help those in need.”

Three people who were injured were transported to hospital in stable, serious and critical condition.

The City of Kelowna has declared a local state of emergency in response to the threat to people and property caused by the crane collapse.

Witnesses said the massive crane collapsed at approximately 11:00 a.m. Video from the scene shows major damage to an adjacent building and at least one vehicle.

The cause of the collapse is under investigation.