President Trump on Friday rejected the notion that the billionaire Elon Musk should be given access to top-secret U.S. plans for a potential military conflict with China, even as he denied a report that such a briefing had been planned to be held at the Pentagon.

“We don’t want to have a potential war with China, but I can tell you, if we did, we’re very well equipped to handle it,” Mr. Trump told reporters in the Oval Office. “But I don’t want to show that to anybody, but certainly you wouldn’t show it to a businessman who is helping us so much.”

Mr. Musk, the chief executive of SpaceX and Tesla and a part-time government staff member, visited the Pentagon on Friday and met privately with Defense Secretary Pete Hegseth.

The New York Times reported on Thursday that Mr. Musk was originally going to visit the Tank, a secure conference room at the building, for a briefing with top military leaders about the China war plan, according to two U.S. officials. A third said Mr. Musk was expected to discuss China, but provided no details beyond that.

The top-secret briefing was to include Adm. Christopher W. Grady, the vice chairman of the Joint Chiefs of Staff; Adm. Samuel J. Paparo, the head of the military’s Indo-Pacific Command; and Mr. Hegseth briefing Mr. Musk on the details of U.S. efforts to counter China in the event of a military conflict, according to the two officials. The discussion was expected to include other matters.