Radisson Hotel Group has notified some of its global loyalty program customers that hackers have stolen their personal information, including their names, addresses, email addresses, and in some cases, their employment and employers’ name and telephone number, rewards member number and frequent flyer numbers.

When it discovered the compromise, it hired investigators and revoked access to the hackers. It flagged the affected members’ account numbers so the accounts could be monitored for suspicious transactions.

Radisson has advised its members to monitor their accounts, review emails from individuals claiming to be a Radisson Rewards representative and to not provide personal information to anyone over the telephone or via email, including their password or user information.