France, Britain and the US were pressing the United Nations Security Council to pass a resolution on Thursday which would allow them to take military action aimed at containing Muammer Gaddafi’s assault on rebel forces in Libya.

After a dramatic decision by Barack Obama, US president, to back calls for international military action against Colonel Gaddafi, the US joined France and Britain’s efforts to get the council to approve a partial no-fly zone over Libya and air strikes against the Libyan leader’s forces.

In London, William Hague, Britain’s foreign secretary, said a draft UN resolution was calling “for all necessary measures short of an occupation force to protect civilians under threat of attack”. French officials said successful passage of the resolution could be followed by immediate military action by France’s jets. “We will be ready to act once the resolution is voted,” a source said in Paris.