He bemoaned the loss of "victims of the Obama-Clinton open border policy," and was joined on stage by people who had lost children and spouses at the hands of illegal immigrants.

Diplomacy abandoned for barnstorming speech

One by one they insisted that if Mr Trump had been in office sooner, their loved ones would still be alive.

In a step that will soothe the concerns of his base but is broadly unpopular with the general electorate, Mr Trump warned all 11 million people currently in the US could face deportation if he wins the White House.

Rejecting so-called "amnesty", he said no one would be able to gain citizenship by simply remaining in the US after entering illegally.

"People will know that you can't just smuggle in, hunker down and wait to be legalised," he said. "Those days are over."