A group of retail merchants will ask the U.S. Supreme Court to hear an appeal involving Federal Reserve rules that allow banks to charge debit card "swipe fees" that retailers view as too high, an attorney for the merchants said on Monday.

Doug Kantor, an attorney with Steptoe & Johnson in Washington, said the merchants believed it was a case the court "ought to hear." An appeals court in March upheld the Fed's rules, which limit the fees businesses pay to banks when customers use debit cards to purchase goods or services.

The rules were required by the 2010 Dodd-Frank law. Merchants argued the Fed's caps on the fees were higher than lawmakers had intended.