A “technical issue” disrupted American Airlines’ nationwide flights early Tuesday, the airline said, at the start of a busy Christmas Eve for travelers across the country.

The Federal Aviation Administration said American had requested a grounding of all of its flights.

“We are currently experiencing a technical issue on all American Airlines flights,” the airline wrote in a post to X.

The post added: “Your safety is our top priority. Once this is fixed, we will get you safely on your way to your destination.” In response to questions from other social media users, the airline said it could not estimate how long the repairs would take.

The airline wrote that there is no “timeframe” yet, but they are “trying to resolve the issue as quickly as possible.”

In a statement sent to ABC News, the airline added: “Our teams are working to resolve the issue as quickly as possible and we apologize to our customers for the inconvenience.”

The disruption will be unwelcome for a record number of Americans expected to travel this holiday season. The Transportation Security Administration said it expects to screen nearly 40 million travelers from Dec. 19 to Jan. 2, a 6.2% increase from 2023.

American Airlines said Dec. 27 and Dec. 20 would be its busiest and second-busiest days, respectively, during the holiday season, which began Dec. 18.

This is a developing story. Please check back for updates.

ABC News’ Ayesha Ali, Clara McMichael and Emily Shapiro contributed to this report.