A sudden power outage brought the world’s busiest airport to a standstill on Sunday, grounding more than 1,000 flights in the US just days before the start of the Christmas travel rush.

Passengers at Hartsfield-Jackson airport in Atlanta were left in the dark when the lights suddenly went out at about 1pm. All outgoing flights were halted, and arriving planes were held at point of departure. International flights were being diverted, officials said.

The airport said a fire had caused “extensive damage” to the complex’s electrical systems. Fire crews doused the flames and repair crews from Georgia Power managed to restore power to all areas after about 11 hours but the incident is expected to wreak havoc on the holiday travel plans of thousands. The cause of the outage is unknown and Georgia Power said such outages were “very rare” .

anthonyfoxx (@anthonyfoxx) Total and abject failure here at ATL Airport today. I am stuck on @delta flight, passengers and crew tolerating it. But there is no excuse for lack of workable redundant power source. NONE! #atlairport #delta

Delta, with its biggest hub operation in Atlanta, was the airline hardest hit. By evening, it had already cancelled 900 Sunday flights and another 300 on Monday, nearly all of them in Atlanta, according to tracking service FlightAware.com.

Robert Mann, an aviation consultant and former American Airlines executive, said it would probably be Tuesday before Delta’s operations in Atlanta returned to normal, and for passengers “it could be most of the week” because there weren’t many open seats on other flights in the last week before Christmas. “Tomorrow is going to be a long and difficult day for everybody,” Mann said.

When flights at Atlanta were grounded for most of one day in April, it took Delta five days and about 4,000 cancelled flights before it fully recovered.

At Southwest Airlines, about 70 Atlanta departures out of 120 scheduled for Sunday were cancelled, an airline spokesman said in an email. United Airlines and JetBlue Airways were among carriers reporting delays or cancellations.

Passengers stranded and unable to fly were being taken to the Georgia International Convention Centre for the night.

City of Atlanta, GA (@Cityofatlanta) The City of Atlanta has mobilized the Georgia International Convention Center and will provide shuttle services for anyone who needs a place to stay for the night. @ChickfilA will provide food for passengers.

Delta passenger Emilia Duca, 32, was on her way to Wisconsin from Bogotá, Colombia, when she got stuck in Atlanta. She said police made passengers who were in the baggage-claim area move to a higher floor. She said restaurants and shops were closed. “A lot of people are arriving, and no one is going out. No one is saying anything official. We are stuck here,” she said. “It’s a nightmare.”

Betsy Klein (@betsy_klein) Pilot, just now: "I still think we're quite a ways from getting deplaned... I certainly thought it'd be taken care of by now... not really sure how long it's gonna take for us to get there." Still no food/water. Toilets have been dumped so won't overflow. We passed 6-hour mark.

Jeff Smith, 46, of Pittsburgh, was stuck in a plane on the asphalt for three hours after it landed. “This is the worst experience I’ve ever had at an airport,” he said.

Sara Melillo was travelling to Pittsburgh from Kenya, where she lives with her husband, Greg Presto, to spend Christmas with his family. The couple were stuck on the asphalt for six hours. They had made stops in Nairobi and Amsterdam and landed shortly after the lights went out in Atlanta. She said the pilot didn’t have a lot of information for the travellers but the plane had airconditioning and attendants offered water and juice a few times. She described the Delta terminal as “big chaos” with not enough customer service for the hundreds of people trying to find a flight or a place to sleep for the night.

With her new boarding pass handwritten and her bags still stuck on a plane, Melillo was hopeful that she and her husband would be able to get a flight in the morning to Pittsburgh, she said as she waited for a lift to a hotel.

Mozell Smith, 68, of Atlanta arrived at the airport hours after the electricity went off. He was headed to Las Vegas with a sister and a friend. “This is terrible. I wish someone would’ve given us a heads-up before we got to the airport,” he said. “I wish there would have been better communication.”

American Airlines reported only a handful of diversions and cancellations because the carrier does not use Atlanta as a hub, airline spokeswoman Alexis Aran Coello.

Hartsfield-Jackson, which serves 104 million passengers a year, is the world’s busiest airport, a distinction it has held since 1998. The airport serves an average of 275,000 passengers daily, according to its website. Nearly 2,500 planes arrive and depart each day.