Republican presidential front-runner Donald Trump criticised fellow candidate Marco Rubio, calling him a "clown" during the conservative Values Voter Summit in Washington on 25 September.

"I mean you have this clown, Marco Rubio. I've been so nice to him," said Trump. The comment drew groans and boos from the crowd as the 69-year-old businessman went on to criticise Rubio's immigration policies.

"But he's in favour of immigration and he has been. It was the Gang of Eight, and you remember the Gang of Eight? It was terrible and then he went down in the polls and you have to stay. You know what, if you believe in something, you have to be true to yourself, you have to be, you have to be. But it was the Gang of Eight and it was really, really – you talk about weak on immigration, nobody weaker."

New York billionaire Trump, who is leading in opinion polls of Republican voters, received cheers from the audience as he waved his family Bible on his way off the stage.