Holiday Inn owner InterContinental Hotels Group (IHG) said it has fully restored service on its systems after it was the subject of a cyberattack earlier this month.

The UK-based hotel group said on September 6 that it had been targeted by hackers who had disrupted its booking systems.

In an update on the incident, the company said that while it had suffered a “period of disruption” in the wake of the attack, within 24 hours it had “reactivated its booking websites and mobile app together with most of its other booking channels and revenue-generating systems”.

IHG said in a statement: “Service at our reservation and customer care call centres has been recovered and all our systems restored. During the disruption in our central systems, IHG-branded hotels continued to operate and were able to take reservations directly.”

External specialists were engaged to investigate the incident, and no evidence of unauthorised access to systems storing guest data has been identified

The company also confirmed it was carrying out a review of security measures in response to the incident.

Following the hack, the BBC reported that a couple from Vietnam had claimed responsibility for the attack, with the hackers reportedly saying they chose to delete company data “for fun” after accessing company systems through a weak password.

IHG did not comment on the nature of the attack but said that it had seen no evidence that the personal data of guests had been compromised.

“We have continued to carry out additional steps as part of our recovery and assurance plans to review and further enhance our security measures,” the hotel group said.

“External specialists were engaged to investigate the incident, and no evidence of unauthorised access to systems storing guest data has been identified.

“We have also reported the criminal activity to law enforcement. We continue to work closely with our hotels and owners throughout this time.”