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The US is repositioning its military assets around Libya even as Britain wants to impose a no-fly zone over the country

Western powers are weighing the military option against Libya's Muammar Gaddafi with US ships being moved to waters closer to Libya and more calls being made for a "no-fly zone" over the North African country.

Russia has however described the no-fly zone idea as "superfluous" and along with France cautioned against moving militarily against Gaddafi without UN authorisation.

“At the moment it seems that the international community is not speaking with one voice on this issue, so in the meantime we will have to wait to see how this plays out,” Al Jazeera’s John Terrett, reporting from Washington, said.

While Jay Carney, a White House spokesman, said on Tuesday that the ships are being moved in order to prepare for contingencies of a chiefly humanitarian nature, he was quick to add that "we aren't taking any options off the table."

Ships to enter Suez

Two US amphibious assault ships, the USS Kearsarge, which can carry 2,000 marines, and the USS Ponce, will pass through Egypt's Suez Canal on Wednesday morning, an Egyptian official said on Tuesday.

The official said the ships would enter the canal at 03:30 GMT.

David Cameron, the British prime minister, on his part said the international community cannot let Gaddafi "murder" his own people, as he justified considerations for a no-fly zone.

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"It's not acceptable that Colonel Gaddafi can be murdering his own people, using aeroplanes and helicopters gunships ... and we have to plan now to make sure that if it happens we can do something to stop that," he said.

"If he starts taking that sort of action we might need to have a no-fly zone in place very quickly."

His comments came as Catherine Ashton, the European Union's foreign policy chief, meet Anders Fogh Rasmussen, the Nato secretary-general, in Brussels, the Belgian capital, over the situation in Libya.

Cameron said he had asked the ministry of defence to work with its allies over plans for a no-fly zone.

He added his government would consider arming opposition groups fighting in Libya.

However, a senior US military official has warned that establishing a no-fly zone in Libya would be a "challenging" military operation.

"My military opinion is that it would be challenging," General James Mattis, commander of US Central Command, told a Senate hearing. "You would have to remove air defence capability in order to establish a no-fly zone, so no illusions here. It would be a military operations - it wouldn't be just telling people not to fly airplanes."

Russia against no-fly zone

Senior Russian officials have ruled out the idea of creating a no-fly zone over Libya.

Sergey Lavrov, the Russian foreign minister, described the idea of imposing limits on Libyan air space as "superfluous" and said world powers must instead focus on fully using the sanctions approved by the UN Security Council over the weekend.

The United Nations general assembly on Monday unanimously suspended Libya's membership of the UN Human Rights Council, citing the government's use of violence against protesters.

A statement said that Libya had committed "gross and systematic violations of human rights".

Dmitry Rogozin,  Russia's NATO ambassador, cautioned against moving militarily against Gaddafi without UN authorisation.

"If someone in Washington is seeking a blitzkrieg in Libya, it is a serious mistake because any use of military force outside the NATO responsibility zone will be considered a violation of international law," Rogozin told Russia's Interfax news agency in Brussels.

"A ban on the national air force or civil aviation to fly over their own territory is still a serious interference into the domestic affairs of another country, and at any rate it requires a resolution of the UN Security Council," Rogozin said.

Mikhail Margelov, a leading Kremlin-allied parliamentarian, said US military action in Libya could "kill the shoots of democracy in the region".

France urges UN mandate

France has said military intervention in Libya could only go ahead with a clear United Nations mandate.

"At the moment I speak, no military intervention is planned," Alain Juppe, the French foreign minister, said.

"Different options can be assessed, notably a no-fly zone. But let me put it clearly here - no intervention will happen without a clear UN Security Council mandate".

NATO says any intervention in Libya would have to be UN-authorised.

 UN Secretary-General Ban Ki-moon said on Tuesday that even more action beyond UN sanctions might be needed, because in Libya "a regime that has lost legitimacy has declared war on its own people."

"It is up to us, the community of nations, to stand against this crime," Ban said in New York.

Barak Seener, a research fellow at the Royal United Services Institute, told Al Jazeera that any UN resolution backing a no-fly zone "would have to demand that the no-fly zone is not open ended and subject to review at certain intervals".

He said as most of the atrocities are taking place on the ground, such a plan could lead to a no-drive zone, or a no-sail zone, and so clear parameters would be needed.

John Rees from the London-based Stop the War Coalition has said such military intervention would be a "prelude to a new war" and a "classic foreign policy blunder".

In an interview with the BBC he said Egypt and Tunisia had proved that people were capable of overthrowing their governments without the help of Western nations.

He added that Libyans were capable of toppling Gaddafi's regime alone, saying large sections of the military had already defected.

Talks over military intervention come after the United Nations Security Council backed a resolution condemning Gaddafi's actions, imposing travel bans and asset freezes on key government figures.

The European Union has also approved its own sanctions on Libya, including an arms embargo and travel bans, and a number of nations, including Britain, the US, Germany, Canada, Switzerland and Austria have announced their own asset freezes.

Source: Al Jazeera and agencies