The breach involved purchases made at Day's Jewelers in November and December, and Maine credit union officials say it could affect thousands of credit and debit cards.

Maine State Police's Computer Crimes Unit is investigating a data breach involving credit and debit cards used to make purchases at Day's Jewelers in November and December.

In a statement, Day's officials say investigators have determined that the suspected breach involved hackers outside of the company. Those who made online purchases were not affected by the breach.

The problem was first noted by credit unions in Maine, whose customers discovered unauthorized purchases on their accounts. Maine Credit Union League President John Murphy says the suspicious activity was noticed during the last several days, and could affect thousands of Maine credit and debit cards issued by both credit unions and banks.

Murphy says credit unions are issuing new cards to affected members. In a statementj, Day's President Jeff Corey says an initial investigation indicates that personal identification was not accessed. The company is urging customers to review their credit and debit card statements, and immediately report any questionable transactions to their card company.

"We apologize for any concerns this may raise with our customers," Corey says. "We are talking directly with any consumer who may have questions or concerns."