Trump said he has a good chemistry with Xi.

"He understands it's a big problem. He's working on it. Now, what am I going to do, start a trade war with China in the middle of him working on a bigger problem, frankly, with North Korea?" Trump said. "We'll see what he can do. Now maybe he won't be able to help. That's possible. I think he's trying, but maybe he won't be able to help and that's a whole different story."

Trump said China has never dealt with the North in a way that it is dealing right now.

"He's working so nicely that many coal ships have been sent back. Fuel is being sent back. They're not dealing the same way. Nobody's ever seen it like that. Nobody's ever seen such a positive response on our behalf from China," he said.

Asked about military options on the North, Trump declined comment.

"I don't want to telegraph what I'm doing or what I'm thinking. I'm not like other administrations, where they say we're going to do this in four weeks," he said. "It doesn't work that way. We'll see what happens. I hope things work out well. I hope there's going to be peace."

Pressed for what he'll do in the event of another missile launch by the North, Trump only said, "We'll find out."

"You look at different things over the years with President Obama. Everybody has been outplayed. They've all been outplayed by this gentleman," he said.

Tensions on the Korean Peninsula have sharply spiked in recent weeks as Washington and Pyongyang have rattled their sabers against each other, with the US sending a massive aircraft carrier strike group to waters off the Korean Peninsula and the North responding with a missile launch attempt, even though it ended in failure.

The two sides have also engaged in a war of words, with American officials repeatedly saying that all options are on the table in an apparent reference to military strikes, and North Korean officials also churning out highly belligerent rhetoric.

On Monday, the North's deputy UN ambassador, Kim In-ryong, told reporters that the US has "created a dangerous situation in which thermonuclear war may break out at any moment on the peninsula." Kim said the North is ready to react to any "mode of war" from the US and will respond in kind to any US missile or nuclear strike.

Earlier Tuesday, Vice President Mike Pence said during a visit to Japan that what the US and other countries are concerned about are the "reckless and irresponsible actions of the regime in Pyongyang."

"The time has really come for North Korea to get the message. As the president says, it's time for them to behave, to listen to the world community, to set aside their nuclear ambitions, their ballistic missile ambitions and be willing to join the family of nations," Pence said on CNN.

"For my part, in some odd way, it's encouraging that they're getting the message and my hope is that they will continue to get the message, not just from the United States, here in Japan and in South Korea, but on an increasing basis from China and countries all over the world that long ago committed to a denuclearized Korean Peninsula," he said. (Yonhap)