An unprecedented shutdown of air travel has been ordered across the United States by the Federal Aviation Authority.

CNN reported an announcement by the FAA that a “communications problem” hit the country’s air route traffic control centres.

Authorities ordered a nationwide ground stop for all US airports, with the FAA ascribing it “to extraordinary circumstances and for reasons of safety”. It did not elaborate on the cause.

The Secretary of Homeland Security ruled out an attack on the US, with a department official blaming a “telecommunications issue”.

The BBC reported just after 5.30pm that Flightradar24 online listed 3,100 flights in the air and bound for US airports. The service said the shutdown was not linked to software outages affecting Microsoft products.

LF Wade International Airport showed an American Airlines flight from Miami International Airport, listed for 10.11pm, as delayed.The causes were unclear.

The stoppage was the first for the US since an incident in 2023 blamed on the pilot notification system going down. Previously, all US flights were grounded in the wake of the September 11, 2001 terrorist attacks on the country.