A Moroccan gunman attempting to hold up a train travelling from Amsterdam to Paris was tackled and subdued by three Americans, assisted by a Briton. The Americans have been thanked by French President Hollande. US airman Spencer Stone said survival instinct led him to react and his friend, Alek Skarlatos of the US National Guard, said the gunman appeared to have no training. The gunman has been linked to radical Islamism.