A program to employ spy satellites for certain domestic uses has been postponed because of privacy concerns. Congress had already provided money for the program, which was to begin this month. But some lawmakers demanded more information about its legal basis and what protections there were to ensure that the government was not peering into the homes of Americans. As a result, the Homeland Security Department is not formally moving ahead with the program until it answers those questions, a department spokesman said.

The program would have expanded access to material gathered by satellites that monitor American territory to agencies involved in emergency response, border control and law enforcement. A new office within the Homeland Security Department, called the National Applications Office, would coordinate requests from civilian agencies for satellite information. Currently, civilian use of the material has generally been limited to monitoring weather and climate changes and to making maps.

Representative Bennie Thompson, Democrat of Mississippi, an opponent of the program, commended the department on Monday for its decision to "go back to the drawing board and get it right."

The department would not say how long it planned to postpone the program. "We are cooperatively working with the Congress to answer any questions that they have," said a spokesman, Andrew Lluberes. "We are totally confident that this is going to go forward."