A small plane has crashed in a forest preserve near Chicago and officials believe two people aboard were killed.

A small Royal Air cargo jet was cleared for landing and was approaching Chicago's Executive Airport when it went down near Wheeling, Illinois.

SLIDESHOW: Small Jet Crashes Outside Chicago

The Lear jet went down in a river.

Airport spokeswoman Laura Witlox said the plane went down around 2 p.m. local time Tuesday and local fire departments were at the scene.

Witlox did not immediately know how many people were aboard and if there were injuries.

The Prospect Heights Fire Department was searching the area.

The FAA has imposed a temporary flight restriction around the crash site.

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The Associated Press contributed to this report.