Libyan rebels are retreating to their stronghold in the eastern city of Benghazi, as Dictator Muammar Gaddafi's forces bombard isolated pockets of resistance in the towns of Misrata and Ajdabiya. The advance has prompted strong calls to impose a no-fly zone over the country, and even a U.S. reversal in support of the idea, as well as the possibility of "other measures" like air strikes to aid the beleaguered opposition forces.

France and England have been the strongest proponents of a no-fly zone. "Only the threat of force can stop Kadhafi. It is by bombarding, with the few dozen planes and helicopters he really has, his opponents' positions that the Libyan dictator has turned the balance," French Foreign Minister Alain Juppe wrote on his blog on Wednesday. "We can/could neutralize his airborne means by targeted strikes… On two conditions: getting a mandate from the United Nations Security Council, the only source in international law for using force; acting not only with the support but also with the concrete participation of Arab nations."

"This second condition is in the process of being satisfied: several Arab countries have assured us that they would take part," Juppe also wrote. Lebanon's ambassador to the U.N. echoed Juppe's call, saying that a "number" of unspecified Arab countries would be willing to participate in the no-fly zone and "other measures to protect the civilian population."

The United States also recently issued statements showing an "urgency" to set up the no-fly zone and other unspecified measures to protect civilians. "We want to do what we can to protect innocent Libyans against the marauders let loose by the Kadhafi regime," Secretary of State Hillary Clinton said in an interview with CBS television. "For the Arab League to call for military action to protect civilians in Libya, against a member of the Arab League, was an extraordinary statement of leadership and real conviction."

Despite mounting international condemnation, the regime has pressed its advantage in recent days, ousting the opposition from key oil ports and nearly every major city in the west. Gaddafi dismissed the no-fly zone while his son Saif al-Islam told Britain's Channel 4 to "wait and see what will happen in the next two days in the east of Libya." Saif also stated that "millions" would be happy to be "liberated from dark forces." So far, government liberation has meant the use of air, land, and sea forces against Libyan towns in rebel hands.

A no-fly zone against advancing troops may not make the difference, according to some experts. "Air strikes would be needed to stop Kadhafi from encircling the city," said Gary Li, a defense expert for the International Institute of Strategic Studies (IISS). Li also noted the regime's willingness to use artillery and ground forces, which would mean at least five to ten days to position sufficient forces to strike or surround the rebel capital of Benghazi.