US Secretary of State Hillary Rodham Clinton has blasted Russia and China as "despicable" for opposing UN action aimed at stopping the bloodshed in Syria, and more than 60 nations have begun planning a civilian peacekeeping mission to deploy after the Damascus regime halts its crackdown on the opposition.
In his most forceful words to date on the Syrian crisis, President Barack Obama said on Friday the US and its allies would use "every tool available" to end the bloodshed by the government of President Bashar Assad.
"It is time to stop the killing of Syrian citizens by their own government," Obama said in Washington, adding that it "absolutely imperative for the international community to rally and send a clear message to President Assad that it is time for a transition. It is time for that regime to move on."
Obama spoke as a group known as the Friends of Syria, led by the US and European and Arab nations, met in Tunisia in the latest effort to halt the Assad regime's nearly year-old suppression of an anti-government uprising.
The group's actions are aimed at jolting Assad and his allies into accepting demands for a democratic transition, even as they are still unwilling to commit to military intervention.
While the Tunisia conference offered nothing other than the threat of increasing isolation and sanctions to compel compliance from Assad, Clinton went on to predict a military coup inside Syria of the kind that ended the old regimes in Egypt and Tunisia.
"We saw this happen in other settings last year, I think it is going to happen in Syria," she told reporters at the end of the meeting. "We also know from many sources that there are people around Assad who are beginning to hedge their bets - they didn't sign up to slaughter people."
Assad allies Russia and China, which blocked UN action on Syria and are eager to head off any repeat of the kind of foreign intervention that happened in Libya, gave no sign they would agree to peacekeepers. Moscow and Beijing have vetoed UN Security Council resolutions backing Arab League plans aimed at ending the conflict and condemning Assad's crackdown.
Their vetoes prompted a particularly strong reaction from Clinton.
"It's quite distressing to see two permanent members of the Security Council using their veto while people are being murdered - women, children, brave young men - houses are being destroyed," she said. "It is just despicable and I ask whose side are they on? They are clearly not on the side of the Syrian people."
The conference, meeting for the first time as a unified bloc, called on Assad to end the violence immediately and allow humanitarian aid into areas hit by his regime's crackdown. The group pledged to boost relief shipments and set up supply depots along Syria's borders, but it was unclear how it would be distributed without government approval.
Syrian government troops kept up the shelling of rebel-held neighbourhoods in the besieged central city of Homs, while thousands of people in dozens of towns staged anti-regime protests. Activists said at least 50 people were killed nationwide Friday.
A Red Cross spokesman said the group evacuated seven people from Baba Amr, a heavily shelled neighbourhood in Homs, to a hospital elsewhere in the city.
The UN estimated in January that 5,400 people were killed in the conflict. Hundreds more have died since, with activists saying the death toll is more than 7,300.
Assad's regime blames the violence on terrorists and armed thugs - not people who want to reform the system.