United Airlines halts all U.S. mainline departures due to tech issue

United Airlines has paused all mainline departures across the U.S. due to a technology issue, the company said in a statement.

“Due to a technology issue, we are holding United mainline flights at their departure airports,” the airline said on Wednesday night. “We expect additional flight delays this evening as we work through this issue.”

This does not affect United Express (regional) flights, and any flight already in the air will continue to its destination, the airline confirmed, according to ABC News.

The Federal Aviation Administration (FAA) confirmed that ground stops for United Airlines flights have been issued at several U.S. airports, including Denver, Newark, Houston, Orlando, and San Francisco.

No further details about the nature of the technology problem were immediately released. The grounding has the potential to affect hundreds of flights and thousands of passengers, though the full extent of the disruption remains unclear.