The man who has revealed he is the source of leaks about the massive American surveillance programme has gone missing.

It is believed Edward Snowden is still in Hong Kong, although he has left the hotel where he was staying.

If the former CIA employee is extradited and prosecuted he could face decades in jail.

A petition posted by supporters on the White House website, hailing him a "national hero" and calling for his immediate pardon, is gathering thousands of signatures.

Jane Little reports.