BBC News with David Austin
The American Secretary of State Hillary Clinton says imposing an effective no-fly zone over Libya would inevitably involve air strikes against Colonel Gaddafi's forces. In a sharp shift of tone, Mrs Clinton said Washington wanted the UN Security Council to authorise air attacks on Libyan tanks and heavy artillery. She said discussions on joint action were underway with some Arab countries, but Egypt said it would not be involved in any attacks.Here's our UN correspondent Barbara Plett.
