U.S. President Donald Trump voiced confidence Saturday that his agreement to meet North Korean leader Kim Jong Un was the right decision, saying that Japan is "very happy with what I'm doing" and that the talks could result in "the greatest deal for the world" that eases nuclear tensions.

"I may leave fast" if progress does not seem possible, Trump said at a televised campaign rally for Republican congressional candidate Rick Saccone in Pennsylvania. Trump said he believes North Korea wants to make peace and that, "I think it's time."

The mercurial U.S. president shocked both those inside and outside his administration on Thursday when he told visiting South Korean officials who had met Kim in Pyongyang for talks days earlier that he would be willing to accept the North Korean leader's invitation to meet.