Britain and France have tabled a draft resolution at the United Nations Security Council that would ban all flights over Libya and prevent air attacks against the month-long rebellion there.
The Arab League has sought such a measure but there's continuing division in the council over military intervention in Libya.
Germany and other countries say there are still many unanswered questions and the United States has not declared its position.
Lebanon helped draft the resolution, with its UN ambassador, Nawaf Salam, saying the threat of force might be enough.
Two eastern towns fall
Meanwhile, forces loyal to Libya's leader, Muammar Gadaffi, have seized the strategic eastern towns of Ajdabiyah and Brega from rebel fighters.
Ajdabiyah fell to a heavy bombardment by ground forces and the oil port of Brega was taken after hours of seesaw fighting.
That opens up the road for government forces to the insurgent stronghold of Benghazi.