Flights to D.C.-area airports were able to resume normal operations after being hit with delays and redirections Sunday after the Federal Aviation Administration ordered a ground stop due to issues with a communication system at an air traffic control facility in Virginia.

"The FAA has paused departures to D.C.-area airports while repairs to a communications system are made at Potomac Terminal Radar Approach Control facility. The facility has switched to a backup system," the FAA said in a tweet Sunday just before 6:30 p.m. ET.

It was not clear exactly what the issue with the communications system was. The FAA did not immediately respond to an overnight request for comment from NBC News.

The issue caused flight delays and redirections across the D.C. area, including all the way to Richmond, Virginia, and Baltimore, Maryland, on Sunday, NBC Washington reported.

The FAA announced less than an hour after pausing departures that flights to D.C.-area airports had resumed, with repairs to the communications power panel complete.

"During the repairs, a back-up system handled communications safely," the FAA said, adding: "Normal operations are resuming."