NATO launched round-the-clock air surveillance of Libya on Monday as the military alliance considered its next steps to address the North African country''s violent unrest.

NATO Secretary-General Anders Fogh Rasmussen reiterated that NATO had no intention to intervene in Libya and would only do so if the U.N. Security Council called for this - something analysts say is unlikely due to Russian and Chinese opposition.

But U.S. Ambassador to NATO Ivo Daalder said planning discussions were well under way at NATO to develop a set of potential options, including a possible no-fly zone, ahead of a meeting of NATO defense ministers on Thursday.

Daalder said the alliance had already agreed to boost surveillance of Libya by AWACS surveillance aircraft to 24 hours a day, giving military planners a detailed view of ground movements as Muammar Gaddafi''s forces do bloody battle with anti-government rebels.

"We''ll have a better picture of what is really going on in this part of the world," Daalder told journalists on a telephone news conference.

The NATO AWACS planes had been providing about 10 hours of Libya surveillance every day as part of existing flights around the Mediterranean. A Pentagon spokesman said that no U.S. aircraft were involved in the new mission.

Rasmussen, speaking at NATO headquarters in Brussels, said he did not believe the international community would fail to act if Gaddafi continued attacks on opponents, although he said that any foreign intervention could risk a backlash.

"That''s exactly the dilemma and that is the reason it is so important we stay in contact with regional organizations like the Arab League and the African Union," he said.

"And the reason why it''s important that any NATO operation takes place in accordance with and pursuant to a U.N. Security Council resolution," he added.

Gulf Arab states on Monday called on the U.N. Security Council to impose a no-fly zone over Libya and requested an urgent Arab League meeting to discuss the situation.

Getting ducks in a row

Rasmussen said NATO was carrying out "prudent" contingency planning should it be asked to take the lead in setting up a no-fly zone, and Daalder of the United States said planners were trying to get their "ducks in a row" by Thursday, when the defense ministers may discuss the issue.

"Our sense is that a no-fly zone is one possibility," Daalder said, although he stressed that it remained unclear how much impact this would have on the violence taking place.

"When you really look at what is going on, we have actually seen a decrease in both fighter and overall air activity over the weekend. It really peaked late last week and it is starting to come down," Daalder said. "To date, the overall air activity has not been a deciding factor in the ongoing unrest."

"A no-fly zone, even if it were to be established, isn''t really going to impact what is happening there today. That doesn''t mean we shouldn''t look at it, and we are and we will. But it is not going to be the solution to every problem."

Over the weekend, leading Republican and Democratic lawmakers urged Obama to do more to help Libya''s rebels, but administration officials remain cautious.

U.S. Defense Secretary Robert Gates reiterated on Monday any intervention in Libya would require broad support.

Analysts say NATO''s emphasis on the need for a U.N. resolution reflects opposition within the alliance to intervention, principally from Turkey, although Germany and other NATO members have also expressed reservations.

Analysts say the lack of U.N. or NATO backing would mean that any no-fly zone imposed by Western forces would have to come about through a smaller coalition, led by the United States and Britain.

"We would prefer to have Security Council backing for whatever steps are taken," State Department spokesman P.J. Crowley told a news briefing, although he noted there was precedent for military moves taken without such a vote.

Daalder said NATO was also looking at how to support humanitarian relief efforts for Libya, including by sending NATO ships to the area and using the alliance''s airlift capability for relief supplies and possible evacuations. "We would expect and hope that ... by the time the defense ministers get there we would agree to move in that direction," Daalder said.