Cancellations and delays caused by a crippling computer system failure have spilled into a second day, the airline said as it continued to wrestle with the crisis.

The outage Monday grounded Delta (DAL) flights for at least six hours, stranding hundreds of thousands of passengers around the globe.

The computer system is back up and departures have resumed, the carrier said, but the aftereffects of the chaos are still being felt.After about 1,000 cancellations Monday, Delta said it expects to call off more than 100 flights Tuesday. Around 200 morning departures are also expected to be delayed.

"Those numbers could grow overnight as Delta works to reset the operation and get crews, aircraft and other elements of the operation back in place," it said.

The airline is offering refunds to passengers on canceled or "significantly delayed" flights, though it did not specify how long a delay has to be to qualify.Delta, the world's second largest airline, said the problem was set off by a power outage at its Atlanta hub and the failure of key systems to switch over to backup power.

The company said it's continuing to investigate what exactly went wrong.