CHICAGO – Weather caused delays and nearly 500 flights to be cancelled at Chicago airports Thursday.

The cancellations came about a week after sabotage at a suburban Chicago air traffic control centre caused more than 2,000 cancelled flights, disrupting travel nationwide.

The Chicago Department of Aviation said Thursday morning that 250 flights were cancelled at O’Hare International Airport and 220 flights were cancelled at Midway International Airport.

On Thursday officials cited weather for the cancellations and delays. Separately, Southwest Airlines says it has cancelled 300 flights at Midway.

On Wednesday, Chicago Mayor Rahm Emanuel said the Federal Aviation Administration needed to “work harder and better and smarter” to restore operations at the airports.

FAA officials say technicians are working around-the-clock to restore telecommunications services at the Chicago En Route Center in Aurora.