WASHINGTON: US Senator John Kerry said Tuesday that the crisis in Syria was "very different" from events that led to NATO-led strikes in Libya and called for a new push to get Russia and China to back UN action.

"Syria is very different," Kerry, a Democrat who chairs the Senate Foreign Relations Committee, said as he met with visiting Israeli Foreign Minister Avigdor Lieberman in the US Capitol.

"This is a very different playing field, very different set of players, very different set of possible prospects," said the lawmaker.

"I think we have to approach it differently. I think we have to condemn what is happening -- and we have. I think we have to work very diligently with China and Russia to see if we can move them, change their positions," he said.

"I think we have to approach it as we are: thoughtfully but very clear about where our preferences lie," said Kerry.

His comments came one day after the United States closed its embassy in Syria and pulled out all its staff, but President Barack Obama shied away from talk of military intervention and vowed to pursue diplomatic means.

The closure came amid deteriorating security as President Bashar al-Assad's government intensified its bloody crackdown, raining rockets and shells on protest hubs in a fresh onslaught that killed at least 66 civilians.

Britain and Belgium recalled their envoys as Western powers sought new ways to punish Damascus amid growing outrage after Russia and China on Saturday vetoed a UN resolution condemning Syria for its 11-month crackdown on dissent.