The US is welcoming what it calls the outpouring of "revulsion" from Arab nations after the attacks in Paris, but wants moderate Muslims around the world to speak up against extremism.

The US Undersecretary of State for Public Diplomacy, Rick Stengel, told me the attacks were not just an assault against France but against freedom of expression around the world.

He added that America is offering whatever support France needs in the aftermath of that attack and is doing everything necessary to protect American diplomats around the world.