A complete power outage at the nation’s busiest airport, the Hartsfield-Jackson Atlanta International Airport, grounded flights Sunday afternoon, threatening to cause a holiday travel nightmare for fliers across the country just over a week before Christmas.

Airport officials said in a news release the power outage has forced the Federal Aviation Administration to suspend outgoing flights and implement a "ground stop" for incoming flights, which "means that flights headed to Atlanta are held on the ground at their departure airport."

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

According to reports to Fox News, 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 is not working.

One woman tweeted out that the “electric exit doors [are] unable to open,” and that “passengers can go no where!” Meanwhile, video posted to social media showed a terminal hallway illuminated only by the light from outside.

“Literal pandemonium at the @ATLairport…baggage claim stuck, passengers can go no where! Which means traffic can’t either. GBI and other law enforcement on site now. Talk about delays!”

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

Almost 2,500 planes arrive and depart Hartsfield-Jackson Atlanta International daily, and the airport averages 275,000 passengers per day, according to the airport's website.