The United States Federal Aviation Administration (FAA) ordered a rare nationwide ground stop on Friday, November 13, temporarily halting departing flights across the country amid serious air traffic control communication problems.

The emergency directive, which affects airports throughout the United States, was issued over what the agency described as “extraordinary circumstances” and safety concerns.

According to Reuters, the FAA instructed that all departing aircraft remain on the ground until further notice, while international flights would be handled on a case-by-case basis.

Aircraft already in the air were permitted to land, but flights awaiting departure were prevented from taking off under the nationwide order.

The unprecedented disruption followed reports of serious communication difficulties within the United States air traffic control system.

Shortly before the nationwide directive, the FAA had halted flights in Chicago because of air traffic control communication issues.

The restrictions quickly extended beyond Chicago, with flights also grounded at Minneapolis–St. Paul International Airport.

Minnesota Public Radio reported that one pilot, addressing passengers waiting to depart, said he had never experienced such a situation.

The FAA's advisory listed an operational window beginning at 4:53 p.m. Eastern Time and extending to 11 p.m., although the restrictions were subject to further updates.

The agency had not immediately provided a detailed explanation of the technical problems or confirmed whether the communication issues were the direct cause of the nationwide shutdown.