A fire at a radar facility that serves Chicago's airports has forced the grounding of thousands of flights, causing delays in the region and across the nation. The incident happened in Aurora, Illinois, when a fire was ignited in the building's basement. It is now extinguished, and authorities are currently investigating.

The fire was reported Friday morning at the Chicago Air Route Traffic Control Center in Aurora, some 40 miles from Chicago, according to NPR. Aurora Police Chief Greg Thomas said the incident involved one of the facilities' contract employees and "is no terrorist act."

"The employee was found in the basement of the radar facility suffering from self-inflicted wounds, police said. He was taken to a hospital and the radar center was shut down and evacuated," he said.

The Chicago Department of Aviation announced at 6 a.m. that the Aurora Federal Aviation Administration tower had been evacuated due to a fire.

"Both O'Hare and Midway International Airports are in a ground stop, meaning no arrivals or departures," the statement said.

The incident has caused massive delays and cancellations in the Midwest, forcing thousands of passengers to arrange new flights or wait until their flights take off. According to USA Today, by 12:25 p.m. more than 1,000 flights had been grounded at O'Hare International Airport. Midway reported some 375 canceled flights.

"Flights have begun arriving and departing to and from the Chicago area at a reduced rate," FAA spokeswoman Laura Brown told USA Today.

Currently investigating the incident is the FAA, ATF and FBI alongside local police. The man found with the self-inflicted wounds is believed to be the one who started the fire. Another man was hospitalized because of smoke inhalation.

Many passengers gathered in O'Hare's Terminal 1 to reschedule their flights. This is the same terminal that was evacuated on Wednesday after a suspicious package was reported, according to WGNTV.