Tens of thousands of Delta passengers around the world were grounded indefinitely Monday after a power outage at its Atlanta headquarters caused a global system-wide computer failure.

Check-in systems, airport screens and even the airline’s website and smartphone apps are affected by the problem, which began at 2:38 a.m. ET.

The airline has suspended departures until the problem can be fixed, while airport agents are writing out boarding passes by hand.

“Our systems are down everywhere,” the airline told customers on Twitter.

Image: At Los Angeles, passengers on late-evening redeye flights to the East Coast to were taken back to the terminal where they were still waiting for information at 3 a.m. PT.


Image: At Los Angeles, passengers on late-evening redeye flights to the East Coast to were taken back to the terminal where they were still waiting for information at 3 a.m. PT.

It later issued a statement confirming the outage.

“A power outage in Atlanta, which began at 2:38 a.m. ET, has impacted Delta computer systems and operations worldwide, resulting in flight delays and cancellations today,” the airline said in a statement.

“The issue is currently impacting flight status information displayed on airport screens, delta.com and some mobile and airport technology. Delta’s information technology team is working to resolve the problem.”

At Los Angeles, passengers on the 12:50 a.m. red-eye to JFK were taken off their plane and back into the terminal with no estimate on when they would be able to depart.

In Las Vegas, some passengers slept on the floor near departure gates awaiting updates from the airline, while at Pittsburgh a long line snaked toward the ticketing counter.

Cynthia Towles, who was at Newark Airport on her way to St. Thomas in the U.S. Virgin Islands, told WNBC: “They didn’t tell us anything. I didn’t get an email, I didn’t get anything. Nothing.”

U.S.-bound passengers at Rome’s Fiumicino Airport told NBC News they had waited more than an hour to check in.

There were similar delays at Tokyo, Japan and at London Heathrow, where staff handed out bottles of water to passengers who had been waiting hours in line.

Amanda Jackson waited more than 90 minutes at Heathrow to check in for a flight to Seattle on her way to Alaska. She reported long lines at Delta counters, along with “a lot of very frustrated people.”

Image: A handwritten Delta boarding pass, issued because the airline's computer system is down, given to passenger Rob Stephenson, 42, of Ann Arbor, Michigan at London's Heathrow Airport.


Image: A handwritten Delta boarding pass, issued because the airline's computer system is down, given to passenger Rob Stephenson, 42, of Ann Arbor, Michigan at London's Heathrow Airport.

Luciano Resende, 40, had been waiting for at least two hours at Heathrow as of 4:40 a.m. ET. He was attempting to make the trip back home to San Francisco via Seattle.

He said airline employees started to manually check-in customers for their their flights but progress had been slow. “I guess it has been a long time since they used the manual process,” Resende told NBC News.