4 July parade

Six dead in 4 July parade shooting near Chicago

The event in the city of Highland Park was suddenly halted shortly after 10:00 local (15:00 GMT), when several shots were heard.

Residents have been urged to stay at home and contact their loved ones to make sure they are safe.

City authorities said 24 people had also been hospitalised.

"We are aggressively looking for the individual responsible for this shooting," Lake County Major Crime Task Force spokesman Christopher Covelli told reporters.