Security has been stepped up in New York and Washington DC amid reports Al Qaeda is planning an attack on the tenth anniversary of 9/11.
According to US intelligence, Al Qaeda has threatened to blow up bridges or tunnels in New York or Washington DC on Sunday.
US president Barack Obama has ordered counter-terrorism forces to “redouble” efforts. Police said the threat was “specific and credible” but as yet unconfirmed.
Police said the public would face car inspections and bag inspections on the subway on the anniversary and a larger number of police cars will be on patrol.
The public have been warned to be “hyper-vigilant”.