When pressed for details during the news conference, Trump called attention to the escalating trade tension between the two countries.

Trump earlier told a U.N. Security Council meeting on nonproliferation of weapons of mass destruction that China was trying to interfere in the upcoming mid-term elections, without providing any evidence. China immediately rejected the accusation during the same meeting, according to reports.

"We have evidence," he said. "It'll come out, yeah, I can't tell you now, but it came — it didn't come out of nowhere, that I can tell you. Now they've actually admitted that they're going after farmers, I mean, I think most of you can cover that."

Trump also doubled down on his earlier accusations that Beijing was looking to meddle in the U.S. congressional elections later this year, but did not offer any specific details. He said China would like to see Trump lose an election because "they've never been challenged like this."

President Donald Trump told reporters on Wednesday that China supposedly respects him for his "very, very large brain," during a news conference where he addressed wide-ranging issues including trade, North Korea and mounting allegations of sexual misconduct against Supreme Court nominee Brett Kavanaugh.

"China now put on $250 billion, and they're paying 25 percent on that. They're paying billions and billions — this has never happened to China, and I like China and I like President Xi a lot," he said in response to a question posed to him by CNBC's Eamon Javers.

"From what I hear, if you look at Mr. Pillsbury, the leading authority on China ... he was saying that China has total respect for Donald Trump and for Donald Trump's very, very large brain. He said, Donald Trump, they don't know what to do," Trump said.

The president was likely referring to Michael Pillsbury, who is senior fellow and director for Chinese strategy at the Hudson Institute, a conservative think tank. Pillsbury told Fox News last month that Beijing viewed Trump as a "superior" president out of the last five or six American leaders that dealt with China and that he was "so smart."

"It's refreshing to see this level of respect for the United States, I haven't seen it in 40 years. Usually the Chinese look down on us as not being very bright," the China-watcher had told the network.

Prior to taking questions from reporters on Wednesday, Trump also said that the trade relationship between China and the U.S. needed to be a "two-way street, and for 25 years, or longer, was not."

The latest round of tariffs targeting U.S. and Chinese goods went into effect on Monday, raising the stakes in an escalating trade spat between the world's two largest economies. The Trump administration levied duties of 10 percent on $200 billion of Chinese products that include furniture and appliances, with the rate set to increase to 25 percent by the end of the year.

It was Washington's third tranche of China-focused levies and part of a strategy to pressure Beijing into changing trade practices that Trump has claimed hurt American companies.

For its part, China said it would impose taxes on American imports worth about $60 billion. Beijing also hit out against the U.S. in a 71-page paper, accusing the U.S. of "trade bullyism practices" that have become "the greatest source of uncertainty and risk for the recovery of the global economy."

— CNBC's Nyshka Chandran and Reuters contributed to this report.

CORRECTION: This story has been updated to correct the spelling of Brett Kavanaugh's name.