Chicago building explosion Injures Six

On Tuesday, an explosion on Chicago's West Side caused a red-brick building to partially collapse, sending eight people to the hospital, including three who had serious or life-threatening injuries, according to the city's fire department.

The top floors at West Washington Boulevard and North Central Avenue have damage, according to pictures and a video the fire department put online. The video showed parked cars with damage from fallen debris and brick strewn around the corner building.

The cause of the explosion, which prompted the evacuation of an adjacent building, was unknown, the Chicago Fire Department said on Twitter.

Chicago's bomb squad and officers from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) were on the scene, the fire department said. At least 10 ambulances were at the site while authorities searched for trapped people.

Firefighters were believed to have rescued everyone from the collapsed building, made up of about 35 units, NBC News said, citing Deputy Fire Commissioner Marc Ferman.