An investigation was under way at a major hotel chain after its online booking system was accessed by hackers, it has been confirmed.
Best Western was targeted on Thursday by hackers who breached IT defences and accessed the chain's booking system.
The Sunday Herald newspaper said details on how to access the site were being sold and that data of thousands of customers who had stayed at Best Western hotels in Europe during last year had been accessed.
Best Western International is the world's largest hotel brand with more than 4,000 hotels in 80 countries.
Tim Wade, head of marketing for Best Western GB, said it was "unlikely" that whoever was responsible got hold of the details of "every booking at every hotel" in Europe because of the way their system worked.
He added: "We are investigating further and that investigation is being led by our team in North America. They are in control of the systems.
"Best Western took immediate action to disable the compromised log-in account in question.
"We are currently in the process of working with our credit card partners to ensure that all relevant procedural standards are met, and that the interests of our guests are protected.
"We continue to investigate the root cause of the issue, including but not limited to the third-party website that has allegedly facilitated this illegal exchange of information.
"We encourage guests with concerns to contact their local Best Western customer service team."