US Secretary of State Condoleezza Rice said on Sunday President George W. Bush's secret order to allow spying on people in the United States was necessary to prevent terrorism, but lawmakers in both parties questioned the action.
Rice, speaking on "Fox News Sunday," said disclosure of the eavesdropping could jeopardise ongoing terrorism investigations.
"The more we get the exposure of these very sensitive programs, the more it undermines our ability to follow terrorists, to know about their activities," she said.