But asked about it on Monday on Fox News, Mr. Trump dismissed that official assessment of China’s disinformation campaign. “They do it and we do it and we call them different things,” he said. He added that “every country does it” before denouncing The New York Times and The Washington Post, which had written about the anti-American disinformation campaigns, as “dishonest” and “corrupt.”

American and Chinese officials appear to realize that finding common ground on the virus could help save lives. Nations have been receiving shipments of medical gear from China, though some of the test kits for the virus have turned out to be faulty. In Italy, Chinese experts have advised officials on how to carry out strict lockdowns.

“Actually this is smart,” said Orville Schell, the director of the Center on U.S.-China Relations at the Asia Society. “Isn’t that the only way to do it? You cooperate where you share interests and you compete and criticize where you don’t. We did it with the Russians in the Soviet days and got some things done.”

Mr. Trump’s earlier attacks on China originated in part with national security officials who aim to hold the Communist Party accountable for the outbreak, and in part from the president’s deep frustration that the pandemic was sinking the American economy, which he saw as key to his re-election.

Mr. Trump has sought to deflect widespread criticism that his administration’s failures had led to the spread of the virus across the United States. And from his campaign in 2016 and the recent trade war, Mr. Trump knows that being tough on China appeals to his supporters, some of his political advisers said.

Meanwhile, Mr. Mnuchin and Mr. Kudlow, who typically counsel the president to try to work more closely with Beijing, had been preoccupied with the crash in the stock markets and a looming recession.

In mid-March, Mr. Mnuchin and Mr. Kudlow were working long hours shepherding an enormous stimulus bill through Congress. In their absence, more hawkish aides, including Mr. Pompeo, Mr. Navarro and Robert C. O’Brien, the national security adviser, had the president’s ear.