CHANDLER, Ariz. (AP) — Multiple people were taken to hospitals after a fire broke out at a commercial building in the Phoenix suburb of Chandler on Monday, authorities said.

It was not immediately clear how many people were hurt, according to Chandler Fire Department officials. The fire broke out around 2 p.m., and its cause was not yet known.

Video from TV station helicopters showed firefighters spraying water on a part of the building’s roof that appeared to have partially collapsed.

Fire crews from Phoenix, Mesa, Tempe and Guadalupe also were working to extinguish the blaze.