Foreign ministers from the 22-member Arab bloc, meeting in Cairo, also left the Libyan leader of more than 40 years increasingly isolated, declaring his government had "lost its sovereignty."

They also appeared to confer legitimacy on the rebel's interim government, the National Libyan Council, saying they would establish contacts with it and calling on nations to provide it with "urgent help."

"The Arab League asks the United Nations to shoulder its responsibility ... to impose a no-fly zone over the movement of Libyan military planes and to create safe zones in the places vulnerable to airstrikes," said a League statement released after the emergency session.

The unusually rapid and bold action for a bloc of nations known for lengthy and acrimonious deliberations appeared to reflect the shifting currents of a Middle East in tumult. Many other Arab governments are facing street protests and rumblings of dissent stirred by the uprisings in Tunisia and Egypt, and their leaders may have felt compelled to act in favor of Libya's rebellion.

League Secretary-General Amr Moussa stressed in remarks afterward that a no-fly zone was intended as a humanitarian measure to protect Libyan civilians and foreigners in the country and not as a military intervention.

That stance appeared meant to win over the deeply Arab nationalist government of Syria, which has smarted against foreign intervention into Arab affairs.

The statement said the Arab League rejected "all kinds of foreign intervention" in Libya but warned that "not taking the necessary action to end the crisis will lead to intervention in Libya's foreign affairs."

The Arab League cannot impose a no-fly zone itself. But the approval of the key regional Arab body gives the U.S. and other Western powers crucial regional backing they say they need before doing so. Many were weary that Western powers would be seen as intervening in the affairs of an Arab country if they began a no-fly zone without Arab approval.