TOKYO (Kyodo) -- Japan Airlines said Thursday that its network suffered a cyberattack earlier in the day, disrupting luggage services and delaying flights before the system was restored.

The airline said customers could once again purchase tickets for both domestic and international flights after a temporary halt, adding that no personal information was leaked and no damage was caused by computer viruses.

JAL said the issues began around 7:25 a.m., causing delays of up to an hour for more than 20 domestic flights. While the airline temporarily halted ticket sales, reservations made earlier remained valid.

Investigative sources said the airline told police that it may have been the victim of a distributed denial-of-service, or DDoS attack, in which networks are overwhelmed by data from multiple sources over a short period.

JAL said it was working to counteract the cyberattack and determine its source, adding that the attack may have a larger effect on its flights. The airline succeeded in temporarily shutting down the router believed to have been compromised.

Chief Cabinet Secretary Yoshimasa Hayashi, the top government spokesman, said at a press conference, "Through the transport ministry, we have requested JAL to repair its system as soon as possible to respond appropriately to affected customers."

Airlines, including All Nippon Airways, Skymark Airlines, Solaseed Air and Star Flyer, have not experienced any cyberattacks and are operating as usual.

Passengers at Tokyo's Haneda airport could be seen questioning staff and anxiously checking their phones, but there was little noticeable confusion at Narita airport in Chiba Prefecture near the capital.

"I was able to check in fine. I've been looking forward to this year-end trip, but it's worrying that there's trouble," said a man in his 30s who was flying from Haneda to Ishigaki Island in the southern prefecture of Okinawa.

A man in his 60s who was traveling to his home in Matsuyama, Ehime Prefecture in western Japan, said, "It's a nuisance during the busy year-end period."