The first challenge to the legality of a U.S. domestic surveillance program is expected to be heard in federal court Monday.

At issue is whether or not the U.S. National Security Agency can monitor communications between American citizens and suspected terrorists overseas.

The challenge was initiated by a prominent civil rights group which says it is illegal for the government to listen to private telephone calls without a court-issued warrant.

The American Civil Liberties Union says the eavesdropping program violates the rights of American citizens.

The Bush administration has asked a federal court to dismiss the case on grounds it could expose government secrets. It says the wiretaps are legal and essential to the war on terror.

The ACLU will ask a judge in Detroit, Michigan to declare the warrantless surveillance program unconstitutional.