PBNJ Productions/Getty Images

(CHICAGO) — At least six people were injured in an explosion at a residential building in Chicago on Tuesday, authorities said.

Of those injured, three are in serious to critical condition, the Chicago Fire Department said.

The “mass casualty” incident occurred at Central and West End avenues.

“This is a confirmed explosion but source of explosion not known,” the fire department said.

This is a developing story. Please check back for updates.

Copyright © 2022, ABC Audio. All rights reserved.