Kofi Annan: Syria 'at a tipping point'

The United Nations special envoy, Kofi Annan, has warned that Syria is at a tipping point and has told President Assad to act now to end the violence.

Syria's ambassadors have been expelled by several European nations and France says it cannot rule out military intervention.

The UN Security Council will discuss its response to the killings in Houla last week, in which most of the victims had been executed, according to a UN investigation.

Andy Moore reports.