US hunts radicalised Americans

America's top diplomat in Pakistan said the US was urgently trying to establish how many Americans may have disappeared overseas to train with al Qaida or other terror groups.

The number was not thought to be large, but ambassador to Pakistan Anne Patterson outlined a possible "nightmare scenario" - people holding US passports receiving terrorist training, then returning legally to the US to commit violent acts.

She told the Pacific Council in Los Angeles that the US was working with Pakistan and other governments to try to identify such people.

She said afterwards "there are more out there than we know about".

Five American Muslims from the Washington DC area were arrested last year in Pakistan, where they face possible terrorism charges.