A senator from President Bush's Republican Party says the president overstepped his authority by ordering an anti-terrorist program to monitor international phone calls without court orders.
Senator Chuck Hagel from the state of Nebraska was asked about the eavesdropping program on Fox television Sunday, after a U.S. court declared the program was unconstitutional.
Another Republican senator, John McCain, defended the plan, saying there is no one who believes the government should not have the authority to perform such wiretapping.
Speaking to NBC television, McCain stressed the need for surveillance operations, following the recent discovery of a plot in Britain to bomb flights to the United States.
Both Senators Hagel and McCain say new laws are needed to help officials monitor terrorist threats.
President Bush has condemned last week's court ruling, saying the surveillance program is a crucial tool for officials battling terrorism.
The Department of Justice has appealed the court ruling and says an order to stop the program will be stayed until the appeal is heard.