A federal appeals court has expressed concern about the government's bulk collection of millions of Americans' telephone records.
The judges are questioning whether it could be extended to bank and credit card records as well.
Questions about the scope of the program arose during arguments Tuesday before the 2nd U.S. Circuit Court of Appeals in Manhattan. The court reserved decision after two hours of arguments.
Groups including the American Civil Liberties Union appealed a judge's December ruling. The judge found that the surveillance program was a necessary extension of steps taken by the U.S. government after the Sept. 11, 2001, terror attacks.
The ruling conflicts with a decision out of Washington, D.C. That court blocked the collection of phone records of two men who had challenged the program.