Alaska Airlines grounded flights at all US airports on Thursday due to a technical issue.

The US carrier said in a statement that it was “experiencing an IT outage affecting operations” and issued “a temporary ground stop.”

The airline did not say how long the outage would last or how many flights were impacted. It said it was “actively restoring our operations” following the outage.

The ground stop also affected Horizon Air, which is operated by Alaska Airlines, according to an advisory by the Federal Aviation Administration.

Alaska Airlines, part of The Alaska Air Group based in Seattle, Washington, primarily operates on the West Coast of the US. It services 140 destinations globally, including 37 states and 12 countries, according to its website.

Last year, the carrier merged with Hawaiian Airlines, which was not impacted by Thursday’s ground stop.

It is the second IT outage affecting the airline this year. In July, an outage halted flights for about three hours.

Alaska Airlines did not immediately respond on Thursday to the BBC’s request for comment.

US air travel has been complicated in recent weeks due to the US government shutdown that began earlier this month. Lack of air traffic controllers showing up for work has delayed flights at several airports.