"I think he's working very hard. I can say that all of the pundits out there saying they've never seen China work like they're working right now," Trump said during a joint news conference with Italian Prime Minister Paolo Gentiloni at the White House, referring to Xi.
"Many coal ships have been sent back. Many other things have happened. Some very unusual moves have been made over the last two or three hours. I really have confidence the president will try very hard," Trump said without elaborating on what the "very unusual moves" are.
Trump appeared to be referencing unidentified fresh measures that China has just taken to pressure Pyongyang after returning coal shipments imported from the North, though the remark may also mean a possible contingency inside North Korea.
Earlier, CNN reported that China put its bombers on "high alert" for a potential North Korean contingency.
Considering Trump spoke just hours after the UN Security Council adopted a press statement condemning North Korea's latest missile launch, he might have referred to Chinese support for the measure, though it is not unusual at all for Beijing to back such a statement.
It was the fifth statement the Security Council has adopted on North Korea this year, all with Chinese support.
"As far as North Korea is concerned, we are in very good shape. We're building our military rapidly. A lot of things have happened over the last short period of time. I've been here for approximately 91 days. We're doing a lot of work. We're in very good position. We're going to see what happens," Trump said.
Trump spoke in response to a question about the mental stability of North Korean leader Kim Jong-un.
"I can't answer your question on stability. I hope the answer is a positive one, not a negative one, but hopefully that will be something that gets taken care of," he said.
Trump said he has held out the prospect of a better trade deal with China if it helps solve the North Korea problem.
"One of the reasons that we're talking about trade deals, we're talking about all of the different things. We're slowing up a little bit. I actually told him, I said, 'You will make a much better deal on trade if you get rid of this menace or do something about the menace of North Korea' because that's what it is. It's a menace. So we'll see what happens," Trump said. (Yonhap)