As tensions between the United States and North Korea escalate over the latter’s missile tests and nuclear capabilities, President Donald Trump said that even though he wanted to handle the situation with diplomacy, a major conflict could not be ruled out.

“There is a chance that we could end up having a major, major conflict with North Korea. Absolutely,” Trump told Reuters in an interview published Thursday. “We’d love to solve things diplomatically but it's very difficult.”

Read: Nuclear Threat Of War From Kim Jong Un's North Korea Is Here To Stay

The comments come on the same day as Secretary of State Rex Tillerson’s statement that the administration was ready to carry out direct talks with Kim Jong Un’s regime to end its nuclear weapons program.

“Obviously, that will be the way we would like to solve this,” Tillerson said in an interview that will air Friday, the WashingtonPost reported Thursday. “But North Korea has to decide they’re ready to talk to us about the right agenda, and the right agenda is not simply stopping where they are for a few more months or a few more years and then resuming things.”

“That’s been the agenda for the last 20 years,” he added.

The recent heightening of tensions between the two countries was sparked by the U.S. decision to send a Navy strike group near the Korean Peninsula, — considered an act of aggression by Pyongyang, in response to which the North Korean government threatened Washington with a nuclear strike if provoked.

In the Reuters interview, Trump acknowledged that North Korea was his biggest global challenge and said he hoped Kim was rational in his approach to the possible conflict.

“He's 27 years old. His father dies, took over a regime,” Trump said of the North Korean leader during the interview, “So say what you want but that is not easy, especially at that age.”

“I’m not giving him credit or not giving him credit, I’m just saying that's a very hard thing to do. As to whether or not he's rational, I have no opinion on it. I hope he’s rational.”

In the Reuters interview, the president was full of praises for Chinese premier Xi Jinping who he met at his Mar-a-Lago estate in Palm Beach, Florida, earlier this month, crediting him with assisting the U.S. in controlling North Korea and its nuclear program.

“I believe he is trying very hard,” Trump said. “He certainly doesn’t want to see turmoil and death. He doesn’t want to see it. He is a good man. He is a very good man and I got to know him very well.”

However, further comments by the president indicated that China’s role in “trying to reign in Pyongyang” came with its set of limitations, despite his claims that he had “established a very good personal relationship with President Xi.”

“With that being said, he loves China and he loves the people of China. I know he would like to be able to do something, perhaps it's possible that he can’t,” Trump added.