Japan Airlines said it was hit by a cyberattack Thursday, causing delays to more than 20 domestic flights but the carrier said it was able to stop the onslaught and restore its systems hours later. There was no impact on flight safety,

Japan Airlines said it was hit by a cyberattack on Boxing Day, causing flight delays and disruption—here’s what we know so far.

The airline also temporarily stopped selling tickets for flights departing Thursday, but said that there was no impact on flight safety.