By Edward Wong and Chris Buckley

WASHINGTON — An American scholar who has advised President Trump on China said late Wednesday that he was not given a visa he sought to attend a recent conference in Beijing, in what he called apparent retaliation for American restrictions on visas for visiting Chinese scholars.

The scholar, Michael Pillsbury, director for Chinese strategy at the Hudson Institute, a conservative think tank in Washington, said he applied for a visa with the Chinese Embassy in Washington on March 22 but failed to get approval to attend the conference last Sunday, which was organized by a research institute in Beijing.

Mr. Pillsbury said that when he raised the issue with a Chinese Communist Party official he knows, the official pointed to a recent New York Times article that said counterintelligence officials at the F.B.I. had been canceling the long-term visas of some Chinese scholars.

Mr. Pillsbury said he took that to imply that his visa application had been stymied in reprisal for the new restrictions.

“They’re very, very clever not to say the visa was denied — just not issuing it in time to get there,” he said in an interview on Wednesday night. Axios first reported on Mr. Pillsbury’s visa problem on Wednesday.

Mr. Pillsbury said American officials told him earlier on Wednesday that they thought China had begun retaliating against the Trump administration’s visa crackdown. He used a Chinese idiom to characterize the move: killing a chicken to scare the monkeys, which means sending a warning by making someone an example.

“In other words, if even Trump’s adviser Pillsbury can be subtly delayed and miss a trade conference, what does that mean to other scholars without a personal relationship with the president?” he said.

Mr. Trump has consulted with Mr. Pillsbury about China and spoken effusively about him, publicly calling him “the leading authority on China” several times.

The Times reported on Sunday that the F.B.I. had rescinded or put on review the visas of as many as 30 Chinese scholars who visit the United States, reflecting growing concern about Chinese intelligence-gathering.

The report drew widespread attention in China, including follow-up reports from Global Times, an influential nationalist tabloid and news site. It said this week that 280 or more Chinese scholars in the humanities and social sciences had seen their visas for the United States canceled or blocked, or had been “harassed” by the F.B.I. It did not cite a source for that number.

“The only plausible explanation is that the self-confidence of the United States really is rapidly rupturing and shrinking,” Global Times said in a separate editorial. “This is the brazen behavior of a ‘police state.’”

Hu Xijin, chief editor of Global Times, wrote on Twitter on Thursday that it was logical that Mr. Pillsbury’s visa problems were tied to the F.B.I.’s visa campaign. Mr. Hu said he believed that “there will be other American scholars who could be denied Chinese visa.”

Such sentiments may seem ironic to American scholars who have been denied permission to visit China in recent decades. They include Perry Link, a professor of Chinese who most recently has taught at the University of California, Riverside, and Andrew Nathan, a professor of political science at Columbia University.

Other researchers and former officials from the United States and other Western countries have said they became wary of visiting China after two Canadians living there — Michael Kovrig, a former diplomat turned researcher, and Michael Spavor, a businessman — were detained in December.

Mr. Pillsbury, who was a Pentagon official during the Reagan administration, has written about China’s military strategy. He is best known for “The Hundred-Year Marathon,” a book about what he says is the Chinese goal of supplanting the United States as the world’s dominant power by 2049. Other China experts in the United States have criticized Mr. Pillsbury’s use of sources and his conclusions.

Mr. Pillsbury has maintained contact with a range of Chinese officials, including ones in the People’s Liberation Army. In 2015, he hosted Col. Liu Mingfu, a hawkish retired officer and author, at a dinner party at his Georgetown home. Mr. Pillsbury has said he believes it is important to have exchanges with Chinese counterparts in order to better understand the Communist Party’s ambitions and strategies.

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Mr. Pillsbury said that until this incident, he had never had a visa request denied or go unapproved since he began visiting China in the late 1970s. He has been to China more than 50 times, and this would have been his fifth visit since Mr. Trump was elected in 2016, he said.

The host of the conference in Beijing was the Center for China and Globalization. Mr. Pillsbury, citing Chinese associates, said that the conference had also invited Wendy Cutler, a former United States trade official, but that she had also failed to get a visa. Ms. Cutler could not be reached for comment late Wednesday night.

In a Chinese online announcement, the center had listed Mr. Pillsbury and Ms. Cutler among those expected to attend the conference. Mr. Pillsbury said he had also planned to attend an event at the United State Embassy hosted by Ambassador Terry Branstad.

A spokesman for the Chinese Ministry of Foreign Affairs, Lu Kang, said at a regular news briefing in Beijing that he did not know the specifics of Mr. Pillsbury’s case. But he said China welcomed American visitors who were “willing to actively encourage Chinese-American exchanges and mutual understanding between the two countries.”

Mr. Pillsbury said he thought his visa problem could also be linked to trade tensions with China, which escalated sharply last year after Mr. Trump announced additional tariffs on Chinese goods. Negotiators from both countries are struggling to reach an agreement that would cool the tensions.

Mr. Pillsbury said he had hoped to meet with former Chinese officials at the Sunday conference who had connections to the current Chinese trade negotiators.

Edward Wong reported from Washington and Chris Buckley from Beijing. Luz Ding contributed research from Beijing.