Senator apologises for posting 'I hope Trump is assassinated', but refuses to resign

A US politician who said on Facebook she hoped Donald Trump would be assassinated has apologised publicly to the president and his family, calling the online posting "a mistake".

But Senator Maria Chappelle-Nadal, a black Democrat, said she has no plans to resign as some Republicans and Democrats in Missouri have insisted since Thursday's post in which she wrote: "I hope Trump is assassinated!"