China's biggest online travel agency Ctrip.com International Ltd was hit by an unknown cyberattack on Thursday, leaving its website and mobile app paralyzed.

The company said in an official statement that the attack, which occurred at 11:09 am, had damaged part of its servers. It said its technicians and engineers were working hard to restores all services.

The company denied rumors that all of its data were deleted and there were no data backups, saying "there is no loss of data on the platform and ordering data are kept intact".