DEARBORN, Mich. —  Federal agents on Wednesday raided several businesses and residences in the Dearborn area thought to be part of illegal money transfer operations that sent as much as $50 million a year to Yemen.

Six people were arrested.

U.S. Customs agents seized records and computers and shuttered some of the businesses, which included convenience stores, service stations and restaurants. Five seizure warrants were issued for banks in the Detroit area and Toledo, Ohio.

Customs officials say the businesses and individuals failed to register their money transfer operations with the Department of Treasury by Dec. 31, 2001.

Under the Patriot Act, money transfer operations are required to register and comply with financial institution reporting requirements.

Officials haven't said whether these raids are terrorism-related. The raid was part of Operation Green Quest, which has hundreds of ongoing investigations into suspected terrorists' finance networks.