President Biden warned on Thursday that China’s struggles with high unemployment and an aging work force make the country a “ticking time bomb” at the heart of the world economy and a potential threat to other nations.

“When bad folks have problems, they do bad things,” the president told a group of donors at a fund-raiser in Park City, Utah.

Mr. Biden’s comments are the latest example of the president’s willingness to criticize China — often during fund-raising events with contributors to his presidential campaign — even as his administration seeks to ease tensions between the world’s two largest economies.

Earlier this summer, at a fund-raiser in California, Mr. Biden called President Xi Jinping of China a “dictator” who had been kept in the dark by his own officials about the spy balloon that flew over much of the United States from late January to early February before being shot down by the U.S. military.

On Thursday night, Mr. Biden said he was trying to make sure the United States has a “rational relationship with China,” but he signaled that he continues to view Beijing as America’s biggest economic competitor.

“I don’t want to hurt China, but I’m watching,” Mr. Biden said in Utah.

The remarks underscore the complicated diplomacy that the president and his administration are engaged in as they attempt to ease tensions with China while limiting the economic and military threats posed by the country and its Communist leadership.

Relations between the two countries grew icy after the spy balloon incident and the more recent discovery that China has been inserting malicious computer code deep inside the networks controlling power grids, communications systems and water supplies around U.S. military bases.

Mr. Biden has said he seeks “competition, not conflict” with China, taking steps to minimize the possibility of direct military clashes with Beijing over the South China Sea and the future of Taiwan.

Top American officials have visited in recent weeks with their counterparts in China. Gina Raimondo, the commerce secretary, is expected to go there in coming weeks.

But the president has moved aggressively to contain China’s rise and to restrict its ability to benefit militarily from the use of technologies developed in the United States.

Mr. Biden signed an executive order this week banning American investment in some Chinese technology industries that could be used to enhance Beijing’s military capabilities. In response, the Chinese government hinted that it would retaliate and accused the United States of trying to “politicize and weaponize trade.”

The president’s comments on Thursday could complicate efforts by both countries to schedule a face-to-face meeting between the two leaders in the coming months. Mr. Biden and Mr. Xi have not met in person since last November, during the Group of 20 summit of world leaders in Indonesia.

The White House has not said whether the two men will have an in-person meeting at the Asia-Pacific Economic Cooperation summit, which is scheduled for later this year in San Francisco. Mr. Xi is expected to attend.