Asked whether that meant assassinating the dictator of the reclusive regime, Trump shrugged.
"Well, you know, I've heard of worse things, frankly. I mean this guy's a bad dude -- and don't underestimate him," Trump responded. "Any young guy that can take over from his father with all those generals and everybody else that probably wants the position, this is not somebody to be underestimated."
Director of National Intelligence James Clapper warned the Senate Armed Services Committee Tuesday about the progress Pyongyang has made on refurbishing and restarting its nuclear facilities.
Trump, a billionaire real estate mogul and reality TV star, said he would "force" the Chinese to deal with North Korea "economically."
"China has control, absolute control of North Korea. They don't say it, but they do, and they should make that problem disappear," Trump said. "China is sucking us dry. They're taking our money, they're taking our jobs and doing so much. We have rebuilt China with what they've taken out. We have power over China. China should do that."
He said the United States' power over China shouldn't be underestimated.
"I wouldn't leave it up to [the Chinese]. I would say, 'You gotta do it. You gotta do it,'" Trump said.
If China refuses, Trump said he would "do it a little more forcefully."
Trump also brought up "that horrible deal with Iran," referring to the controversial nuclear deal between the Obama administration and the Islamic Republic.
"The closest partner of North Korea is Iran. Why didn't we put something in there when we're making a deal, and we're giving them $150 billion -- why didn't we do something with Iran where Iran gets in, and we force Iran to get in and do something with North Korea?" Trump said. "We don't do anything. We should have, when we made that deal. That deal is a horror show. It's one of the worst I've ever seen."
Secretary of State John Kerry should have asked Iran for their help, Trump said, adding that "nukes" are a "game changer," and if it weren't for nuclear weapons, we shouldn't be in the Middle East.