Computer thieves stole roughly $35,000 in incentive awards from about 650 clients of Carlson Rezidor Hotel Group, the company confirmed Wednesday.

Carlson Rezidor late last week sent e-mail notices to the affected customers, who accumulated Club Carlson Gold Points through hotel stays and food and beverage purchases, said Rachael Marret, who as senior vice president of customer engagement oversees loyalty programs.

The company was tipped off to the system attack about 12 days ago by suspicious activities in Club Carlson accounts, which included changes in account passwords and e-mail addresses and conversions of Gold Points to PayPal credits or electronic gift cards, Marret said.

The affected customers represent a small portion of the 12 million Club Carlson members. But they were asked to check recent Club Carlson account transactions and e-mail information and to change their account passwords. Any customers who lost Gold Points will have them replaced by the company, Marret said.

The customer accounts did not include any customer financial or personal information except for phone numbers, e-mail addresses and street addresses, she said. The phone numbers have now been deleted.

The firm is still investigating the theft, Marret said.

Carlson Rezidor, based in Minnetonka and Brussels, Belgium, operates about 1,000 hotels around the world under the Radisson, Radisson Blu, Park Plaza, Park Inn by Radisson, and Country Inns and Suites by Carlson brands.