A complete power outage at the busiest airport in the U.S., the Hartsfield-Jackson Atlanta International Airport, grounded thousands of flights on Sunday afternoon.

Almost 2,500 planes arrive and depart daily, and the airport averages 275,000 passengers per day, according to the airport’s website.

The airport said in a statement that the power outage had forced the Federal Aviation Administration to suspend outgoing flights and implement a “ground stop” for incoming flights.

This “means that flights headed to Atlanta are held on the ground at their departure airport,” the airport said.

“The #FAA has put in a ground stop for flights headed to @ATLairport due to a power outage affecting the airport terminals.

“The FAA Tower can operate normally, however, departures are delayed because airport equipment in the terminals is not working.

“Officials are reportedly on the scene ‘working to remedy the situation’, Atlanta Airport said, adding “there have been no reports on when the power is expected to be restored”.

“International flights will be diverted to land at other airports”, U.S. Customs and Border Protection tweeted.

According to reports, the blackout was caused by a construction crew cutting a power line.

Airport officials said the outage happened just after 1 p.m. on Sunday.

The airport reported on its Facebook page that departures were delayed because airport equipment in the terminals was not working. (NAN)