WASHINGTON – Senior U.S. officials yesterday highlighted the risks of imposing a “no-fly” zone over Libya as a way to help rebels facing counterattacks by Muammar Gaddafi’s forces, saying such a move was not imminent.

“Let’s just call a spade a spade,” Defense Secretary Robert Gates told a budget hearing in the House. “A no-fly zone begins with an attack on Libya to destroy the air defenses.”