(CBS SF) — Bay Area flights to and from the Chicago area are canceled and delayed Friday morning because of a fire at a Federal Aviation Administration

The Chicago En Route Center was evacuated Friday morning just before 4 a.m., 6 a.m. local time in Chicago.

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The FAA initially issued a ground stop for flights in the Chicago area.

Some flights were still permitted to land at Chicago area airports, and others were rerouted.

Brian Horne, the airport duty manager at San Francisco International Airport, said six flights to the Chicago area were cancelled Friday morning, and four arriving flights were cancelled.

He said flights departing to the Chicago area Friday that are still scheduled are experiencing delays of about one to two hours.

Mona Hernandez, spokeswoman for Oakland International Airport, said all flights to and from the Chicago area before 11:30 a.m. have been cancelled.

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She said later flights still appear to be on schedule. Mineta San Jose International Airport spokeswoman Rosemary Barnes said two Chicago-area flights were cancelled Friday morning.

She said there aren’t any other flights to or from the Chicago area canceled or delayed.

The FBI, ATF and the Aurora police and fire departments are investigating this morning’s incident at the FAA facility.

The FAA is warning there may be flight delays throughout the day, and travelers should contact their airlines to check updated flight schedules.

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