NYPD police car convoy
Media playback is unsupported on your device
Video

NYPD commissioner fears 9/11 anniversary attack

The New York City police commissioner has told the BBC of his concerns that al-Qaeda could attempt another attack to mark the 10th anniversary of 9/11.

He has said his fears were based on intelligence seized during the raid on Osama Bin Laden's compound earlier this year.

The BBC spent time with the New York Police Department as it prepared a massive security operation.

Gordon Corera reports.

Go to next video: How NYPD has evolved to face terror threat