U.S. carrier Alaska Airlines said late on Thursday it was restoring its operations after a technology outage earlier in the evening had grounded its flights at all airports.

The ground stop also applied to Alaska Airlines' subsidiary Horizon Air, a Federal Aviation Administration advisory showed. The ground stop was requested for a period of almost three hours.

The airline also briefly grounded all of its flights in July for about three hours due to an IT outage.

"Alaska Airlines is experiencing an IT outage affecting operations. A temporary ground stop is in place. We apologize for the inconvenience," Alaska Airlines said in a statement issued on social media.

Nearly three hours later, it posted: "We are actively restoring our operations following an IT outage."

The airline also responded on social media to customers who were posting concerns and complaints online.

"Unfortunately, we are experiencing an error on our system, but our IT team is working to get this resolved as soon as possible," it said earlier in the evening, in response to an X user who asked if the airline's app was also having issues.

It issued a similar response to a user who asked about booking problems on the airline's website. (Reporting by Kanishka Singh and Ismail Shakil; Editing by Jamie Freed and Christopher Cushing)