President Barack Obama has said
Republican nominee Donald Trump is unfit to be president, and questioned
why his party still supports the New York billionaire's candidacy.
Mr Trump has been sharply criticised for attacking the parents of a fallen US solider who spoke out against him.
He has also been condemned for backing the Russian annexation of Crimea. Mr Obama said he had had policy differences with previous Republican presidents and candidates but added that he had never thought they could not function as president.