BBC News with Marion Marshall

The United States, Britain, France and Germany have demanded that President Bashar al-Assad of Syria leave office following the violent suppression of street protests against his leadership. It's the first

explicit

call from the US and its allies for Mr Assad to step down, although Washington had previously said Syria would be better off without him. From the American capital, here's Jonny Dymond.

Once Bashar al-Assad was cited by the US as a reformer and a possible peacemaker, but after five months of bloodshed, the relationship between Washington and Syria's president has ended. President Obama on Thursday signed an order freezing Syrian assets and cutting commercial links, and after months of hardening rhetoric, the president called on Bashar al-Assad to stand down. British, French and German leaders

swiftly

followed suit

. But the US made it clear that it will not intervene militarily to try and topple President Assad. "It is," said Barack Obama, "

up to

the Syrian people to choose their own leader."

The Israeli government says it will respond with full force to attacks by gunmen in southern Israel that killed at least seven people. Israel's Defence Minister Ehud Barak said there had already been one air strike on the Gaza Strip. At least six Palestinians were killed. The Israeli Prime Minister Benjamin Netanyahu has described the attacks in southern Israel as an assault on his country's