France and Britain have warned Syria's President Bashar al-Assad that military action to secure safe zones for civilians inside the country was being considered despite the paralysis of the UN Security Council over how to end the 17-month conflict.
While the Security Council impasse between western nations and Russia and China means a resolution to approve such a move appears impossible, countries could act outside the authority of the world body and intervene, as happened in Kosovo in 1999.
"We're ruling nothing out and we have contingency planning for a wide range of scenarios," British Foreign Secretary William Hague told a news conference at the United Nations ahead of a meeting of Security Council foreign ministers to discuss how to ease Syria's humanitarian crisis.
"We also have to be clear that anything like a safe zone requires military intervention and that of course is something that has to be weighed very carefully," Hague said.
Turkish Foreign Minister Ahmet Davutoglu, who is attending the meeting, has urged the United Nations to protect displaced Syrians inside their country, but Assad dismissed talk of a buffer zone.
Creating a buffer zone for displaced Syrians would be difficult because a UN Security Council resolution would be needed to set up a no-fly zone to protect the area, and Russia and China would not approve such a move, diplomats said.
It is not the first time Russia has posed difficulties for the United States and its allies on the Security Council. In the 1990s, Moscow strongly supported Serbia in the Balkan Wars and acted as Belgrade's protector on the council.
After an ineffectual UN presence failed to stop genocide in the 1992-1995 Bosnian War, the United States and its European allies infuriated Russia by bypassing the deadlocked Security Council and turning to Nato to halt the Serbian onslaught in Kosovo with a bombing campaign against Serbia in 1999.
As Syria spirals deeper into a civil war, the 15-member council is paralysed as Russia and China have blocked three Western-backed resolutions that criticised Syrian President Bashar al-Assad and threatened sanctions.
France, which is council president for August, had hoped the body could unite to deal with a shortfall in humanitarian aid and convened today's (NZ time) meeting, which will also be attended by ministers from Syria's neighbours Turkey, Lebanon, Jordan and Iraq.
"If Assad falls quickly, then the reconstruction can take place, but if sadly the conflict continues then we have to examine various solutions. We have to be realistic," French Foreign Minister Laurent Fabius told the joint news conference with Hague.
AID FOR REBEL ZONES
But the absence of the US, Russian and Chinese foreign ministers at today's meeting highlights the Security Council's failure to end Syria's conflict, which the United Nations says has killed nearly 20,000 people.
Less than half the council members have sent ministers, and of the permanent members - the United States, China, Russia, Britain and France - only Fabius and Hague are attending.
The two countries announced an increase in their humanitarian aid - £3 million (NZ$5.93m) from London and €5 million (NZ$7.83m) from Paris - and called on other states to boost their commitments.
Diplomats said the meeting would not produce any further action on Syria from the Security Council.
"We wanted a resolution on humanitarian issues, but we faced a double refusal," said a French diplomat, who did not want to be identified. "The United States and Britain believe we have reached the end of what can be achieved at the Security Council, and Moscow and Beijing said that such a resolution would have been biased."
Fabius said Paris was channelling some of its aid to areas of Syria no longer under government control so that local communities can self-govern, encouraging people not to flee Syria to neighbouring countries.
More than 200,000 Syrians, and as many as 300,000 according to some aid groups, have poured out of Syria since the uprising against Assad's rule began last year, while up to 3 million are displaced. Turkey, which has seen the highest refugee influx, wants a solution to the problem.
The Security Council is due to hear from Deputy Secretary-General Jan Eliasson, UN High Commissioner for Refugees António Guterres and ministers from Turkey and Jordan.
Algerian diplomat Lakhdar Brahimi, who will replace Kofi Annan as the UN-Arab League Syria mediator on Saturday, will also attend but will not brief members. Annan blamed the Security Council impasse for hampering his six-month-old bid to broker peace and leading to his decision to step down.
Brahimi met informally with the Security Council on Wednesday and his spokesman, Ahmad Fawzi, told reporters he had been in "listening mode" while he works out how to approach the Syria conflict.
While Thursday's meeting was focusing on the humanitarian crisis, Fabius and Hague urged members of Assad's government and military to defect and renewed their call for Assad to be held accountable before the International Criminal Court.
"Assad is a criminal and a criminal must be judged and punished," Fabius said.