Japan Airlines says it has resolved a system failure that began on Thursday morning. The carrier says it was caused by a cyberattack, but there was no customer data leakage.

The attack occurred shortly before 7:30 am. The airline says it led to the cancellation of several flights and more than 60 delays. The company suspended ticket sales for Thursday flights, but has now resumed them.

Japan Airlines says it apologizes to customers and others affected by the inconvenience. It also says there is no impact on flight safety.

Investigative sources said this could be a "DDoS attack," in which attackers send massive amounts of data to websites to make them crash.