(Reuters) – Michaels Stores Inc, the biggest U.S. arts and crafts retailer, on Friday confirmed that there was a breach of certain systems that process payment cards at its U.S. stores and that of its unit, Aaron Brothers. The company said in January that it was working with federal law enforcement officials to investigate a possible data breach. While the affected systems contained certain payment card information, there was no evidence that those data were at risk, the company said in a statement on Friday. Michaels said it was working with law enforcement authorities, banks and payment processors, and that the malware no longer presents a threat.