A special meeting in Cairo voted to ask the UN Security Council to impose the policy until the current crisis ended.

The UK and France have pushed for the idea, but have failed so far to win firm backing from the EU or NATO.

Libyan rebel forces have meanwhile suffered fresh setbacks including the loss of the key oil port of Ras Lanuf. Reports suggested that the rebel front line had been pushed back even further back, towards the town of Ujala.

The Arab League vote for a no-fly zone was opposed only by Syria and Algeria, reports from the Cairo meeting said.

NATO has previously cited regional support for the idea as a key condition before it could possibly go ahead.

The US welcomed the Arab League's call, saying it strengthened the international pressure on Col Gaddafi and support for the Libyan people.

The US Defense Secretary, Robert Gates, had earlier been quoted by French news agency AFP as saying it was still not clear whether it was the right policy.

Russia, which wields a veto on the UN Security Council, has expressed serious reservations on the issue.