Republican presidential front-runner Donald Trump said that he'd like to punch a protester in the face and bemoaned the 'old days', as the man was escorted out by security on Monday night.

Las Vegas: Republican presidential front-runner Donald Trump said that he'd like to punch a protester in the face and bemoaned the 'old days', as the man was escorted out by security on Monday night.

Trump made the comments after the protester was allegedly found disruptive at a Las Vegas arena, filled with thousands of Trump supporters, on the eve of the Nevada caucuses.

The guards were being 'very gentle' says Trump, allowing the man to walk out of the arena smiling.

Trump said, "You know what I hate? There's a guy totally disruptive, throwing punches. We're not allowed to punch back anymore."

Reporters didn't see why the man was ejected, and it was unclear whether he had actually thrown any punches.

Still, Trump went on, "I love the old days. You know what they used to do to guys like that when they were in a place like this? They'd be carried out in a stretcher, folks."

The crowd thundered in agreement.

"I'd like to punch him in the face," Trump added.

AP