US Secretary of State John Kerry said President Bashar al-Assad is a "desperate leader" and praised the opposition as the legitimate voice of the Syrian people.
Mr Kerry confirmed the US will take "further steps" to help the opposition, which is faced by "brutal regimes" and Iranian forces.
He also added that the US will provide $60 million "immediately in non lethal assistance" to aid Syria opposition.
More top news
An ejector seat manufacturer is to be prosecuted over the death of Red Arrows pilot Sean Cunningham at RAF Scampton in November 2011.
Police said the "active shooter" had since been shot by officers and they were not seeking any other suspects.
Rain will continue spreading in from the southwest, remaining heavy, especially in western areas.