The boss of foreign exchange operator Travelex says the company is making "good progress" in restoring its online services after a cyber-attack detected on New Year's Eve forced it to shut down its systems.

Chief executive Tony D'Souza has appeared in a video on the company's Customer Information Hub webpage to reassure partners and customers that the situation is under control and Travelex services will be up and running again soon.

According to D'Souza, no customers' data has been breached.

"We engaged internationally renowned cyber experts to run forensic analyses and we have not, to date, uncovered any evidence to suggest that any customer data has left the organization."

The root cause of how the malware entered is still under investigation by the National Cyber Security Centre and London's Metropolitan Police.

"You will understand that this is a matter under investigation and we are working with the relevant authorities," said D'Souza.

"It is not appropriate to say any more at this stage."

Travelex provided no information on whether the company paid the ransom of almost $6m (£4.6m) requested by the cyber-attackers.

The Travelex website remains offline but the company is back to serving customers electronically in its UK stores and has announced that testing in some branches outside the UK will begin later this week.

VAT refund services in UK airports will also be accessible to customers.

The global foreign exchange operator is prioritizing the UK, its largest market.

The company has announced that the recovery will be phased and will prioritize "integrity and security" and focus on the enhancement of its infrastructure.