Republican senator Lindsey Graham tells President Donald Trump to ‘knock it off’ with tweets about the former FBI chief James Comey, during an interview on CBS program Face the Nation. ‘You may be the first president in history to go down because you can’t stop inappropriately talking about an investigation that, if you just were quiet, would clear you’

• Senators sound calls to release Comey tapes as Trump attacks ‘cowardly’ leak