US confirm al-Qaeda behind threat of attack on 9/11 anniversary

Ten years on from the attacks of 9/11, America has warned that al-Qaeda still poses a real and significant threat.

The US Secretary of State, Hillary Clinton, has said the terrorist organisation is behind what officials are calling a credible but unconfirmed threat of an attack, in New York or Washington, to coincide with the tenth anniversary of 9/11.

Police in both cities have stepped up security in response to the warning.

Laura Trevelyan reports from New York.