The United States, Britain and France pressed the UN Security Council to back military action to halt Muammar Gaddafi's offensive against rebels, diplomats said.
With Gaddafi forces claiming to be at the gates of the rebel capital Benghazi, French Foreign Minister Alain Juppe went to New York to press the case to approve "necessary measures" that would fall short of sending troops into Libya.
Envoys from the 15-nation council held new talks and France, Britain and the United States are pressing for a Security Council vote today.
France and Britain have led a campaign for a no-fly zone over Libya. While this is resisted by China, the United States has taken an increasingly tough line seeking broader measures against the threat posed by Gaddafi.
The United States has said a no-fly zone may not be enough and stressed the need for strong Arab participation in any operation.
US ambassador Susan Rice said after yesterday's talks finished: "We need to be prepared to contemplate steps that include, but perhaps go beyond, a no-fly zone."
Rice said the United States wanted "a broad range of action which will protect civilians and halt the killings" by Gaddafi's forces.
The chief of the US Air Force, General Norton Schwartz, told US lawmakers in Washington that imposing a no-fly zone over Libya "would not be sufficient" to halt Gaddafi's forces.
US Secretary of State Hillary Clinton said on a visit to Tunis that the United States "will look for a broad base of participation, including from Arab nations."
France, Britain and Lebanon have tabled a draft UN resolution "broadening the scope of sanctions and opening the path for using the necessary means to stop Gaddafi's offensive," said a French foreign ministry statement.
The draft resolution now being negotiated "calls for an immediate ceasefire in Libya and authorises states to take the necessary measures to protect the threatened civilian population, especially in Benghazi," French foreign ministry spokesman Bernard Valero said.
NATO has already planned for a no-fly zone and its chief Anders Fogh Rasmussen urged the UN Security Council to quickly agree a resolution, warning "time is running out" to stop Gaddafi.
"If Gaddafi prevails it will send a clear signal that violence pays. That would be unacceptable from a humanitarian and democratic perspective," Rasmussen said.
"NATO stands ready to protect the civilian population if there is a demonstrable need, clear legal basis and strong regional support."
Technical experts held talks today on a draft resolution drawn up by Britain, France, the United States and Lebanon, acting for the Arab League.
Ambassadors were to start new formal meetings before Juppe's arrival.
China has opposed military action, Germany has also spoken out against no-fly zones. Russia, India, South Africa and other nations have expressed various degrees of doubts, diplomats said.
Britain, China, France, Russia and the United States are permanent members of the council who can veto any resolution.
"It has to be stressed that this resolution could be greatly changed before it comes to a vote," said one Western diplomat at the UN, speaking on condition of anonymity.
Russia had wanted a resolution demanding a ceasefire to be passed first, but this did not get enough backing to go for a vote. French ambassador Gerard Araud said there was a demand for a ceasefire in the new draft, "with teeth" to back up the threat.
Germany yesterday rejected the idea of a no-fly zone in Libya saying it could lead to "war". "We have no wish to and we cannot take sides in a north African civil war," Foreign Minister Guido Westerwelle said in Berlin.