A two-alarm fire burned part of the John Hancock Center in Chicago

Screen grab via Chicago Fire Media

CHICAGO (AP) -- Authorities say a fire that broke out about halfway up the John Hancock Center, one of Chicago's tallest skyscrapers, has been put out. One person was injured.

Flames and thick smoke poured out of an east side window on the 50th floor Saturday. The fire in a residential unit burned for about a half-hour.

The iconic 99-floor building completed in 1970 also has offices, shops and an observation floor popular with tourists.

Five people were injured but the fire has been extinguished. A spokesman could not immediately be reached to provide details.

Firefighters were conducting floor-by-floor searches of hallways and stairs to ensure people were safe, and advised residents to stay inside their units unless they had problems with smoke.

The cause is being investigated.