By David Shepardson

WASHINGTON (Reuters) – U.S. airlines have canceled hundreds of flights at three major U.S. airports this week after a series of coronavirus cases involving air traffic control personnel.

The U.S. Federal Aviation Administration (FAA) temporarily closed the air traffic control tower at John F. Kennedy Airport in New York early Friday before reopening it around 11:30 a.m. ET (1530 GMT). The FAA also shuttered part of the Indianapolis Air Route Traffic Control Center for cleaning after workers tested positive for the coronavirus.

The FAA said a technician at JFK had tested positive and air traffic controllers had been operating earlier from an alternate location on airport property.

American Airlines Group Inc <AAL.O> said it canceled 20 of its 68 scheduled departures from JFK on Friday due to a reduced incoming arrival rate after traffic control was shifted to the other location.

In Indiana, after an air traffic control supervisor tested positive, the FAA vacated work areas at the Indianapolis Air Route Traffic Control and flights through the airspace handled by those sectors were rerouted.

Air traffic control towers remain closed at Chicago Midway and Las Vegas airports after other coronavirus cases were reported earlier this week.

Airlines have canceled more than 700 flights on Thursday and Friday at Las Vegas and more than 800 over the last two days at Midway, according to flightaware.com.

Southwest Airlines <LUV.N> has resumed operations in Chicago after canceling more than 200 flights on Thursday. The airline said it had also canceled another 150 flights at Chicago and more than 165 flights at Las Vegas airport on Friday.

On Thursday, the FAA placed a temporary flight restriction over Midway to allow only commercial flights and other authorized flights after a number of local private pilots began using the airport for touch-and-go landing practice.

(Reporting by David Shepardson; Additional reporting by Tracy Rucinski; Editing by Bill Berkrot, Chris Reese and Richard Chang)