Tornadoes halt Chicago air traffic as residents urged to seek shelter

At least eight tornadoes hit north-eastern Illinois, with no immediate reports of injuries

Tornadoes and thunderstorms battered the Chicago area on Wednesday, forcing airports to halt air traffic and prompting officials to advise residents to seek shelter as tornado sirens echoed through the third largest US city.

The National Weather Service reported that a tornado touched down near Chicago's O'Hare international airport on Wednesday evening - one of at least eight tornadoes to hit north-eastern Illinois, including four in Cook county.