Authorities say a natural gas explosion has leveled at least one multistory building in Springfield in western Massachusetts and a number of people were injured.

A spokesman for Springfield Mayor Domenic Sarno says there's no word yet on whether anyone was killed in the explosion late Friday afternoon.

Police Captain William Collins tells WGBH News that one building on Worthington Street was destroyed, and a building across the street sustained heavy damage.

Collins says gas crews were looking for the source of a gas leak before the explosion occurred.

The force of the blast sent bricks and glass flying through downtown streets. Police Sergeant John Delaney says authorities were evacuating the commercial and residential area on Friday evening.