CHICAGO, Ill. -- A helicopter crashed near the junction for I-94 and I-57 on Saturday night, according to Chicago Fire Department. 

Four occupants were taken to various hospitals. Three passengers are in stable condition and one is in critical condition, according to Chicago Fire Media. 

Along with Chicago officials, the Federal Aviation Administration are heading to the scene to investigate the crash. 

The helicopter was a Eurocopter 135 air ambulance, according to the FAA.

The crash happened around 9:30 p.m. but did not land on the expressway. 

Officials do not know where the helicopter was coming from or where it was going. 

Air ambulance down four PT's at this time all red. Update to follow. 4-1-8 pic.twitter.com/TEeq0RK6QQ

— Chicago Fire Media (@CFDMedia) July 8, 2018