On Friday, Mr. Trump said that Mr. Kim had discussed his country’s missile tests in his letter and that Mr. Kim wrote that he was not happy about carrying them out.

“But he wasn’t happy with the testing; he put that in the letter,” Mr. Trump said. “In the meantime, I say it again: There have been no nuclear tests. The missile tests have all been short-range. No ballistic missile tests. No long-range missiles.”

Mr. Trump’s comments partly contradicted South Korea’s analysis of the missiles North Korea has launched in recent weeks. The South said that at least some of them were short-range ballistic missiles. Under a series of United Nations resolutions, North Korea is banned from testing ballistic missiles.

According to Mr. Trump, the North Korean leader also indicated that he was not happy with the joint military exercises between South Korea and the United States. Mr. Trump said he didn’t like them either because South Korea didn’t pay enough for them.

“I’ve never liked it. I’ve never been a fan,” he said. “You know why? I don’t like paying for it. We should be reimbursed for it, and I’ve told that to South Korea.”

South Korea and the United States are about to begin a new round of talks on how to divide the cost of maintaining 28,500 United States troops in South Korea. South Korea paid about $925 million this year but Washington wants Seoul to increase its contribution.

Despite the lack of progress in talks with North Korea and the recent missile tests, Mr. Trump and Mr. Kim have refrained from criticizing each other. They have also exchanged several letters since last year, keeping the momentum for diplomacy alive.