President Trump on Friday lashed out personally at Chinese President Xi Jinping, calling him an “enemy” in a dramatic escalation of rhetoric that could signal a deeper shift in his administration’s increasingly confrontational strategy toward China.

Despite the rising tensions on trade, Trump had sought to maintain good personal relations with Xi, calling him “my friend” in a tweet earlier this month and praising his leadership. He has even refrained from criticizing Xi over China’s handling of massive pro-democracy demonstrations in Hong Kong that Beijing has blamed on U.S. influence.

But Trump dropped all pretense Friday in series of tweets in which he directed American companies to ditch China and declared that the United States “would be far better off” without dealing with the world’s second-largest economy. The president’s frustration over a lack of progress on trade talks with Beijing and signs of weakness in the U.S. economy boiled over as he attacked both Xi and Federal Reserve Board Chair Jerome H. Powell, asking in one tweet “who is our bigger enemy” between the two.

Even Trump allies who have cheered his showdown with Beijing are saying that the president’s statements may foreshadow a possible sharper break between the two countries.

“It’s a striking departure for American policy on China; it’s even a striking departure from Trump’s policies and comments on China of just a few weeks ago,” said Gordon Chang, an author and frequent Fox News commentator who espouses hawkish views on China.

“Trump is capable of a head fake, but I do not get a sense this is a head fake,” Chang added. “This is frustration on the part of the president. Today strikes me, given the virulence of the tweets, that we’re seeing another turn toward what we could call a breaking-off of relations with China.”

White House aides declined a request to elaborate on Trump’s tweets. But officials have said that the president and his advisers have grown increasingly convinced that there is little hope for a trade deal. Last week, the Trump administration announced it would postpone a new round of tariffs on Chinese goods until later in the year over fears that they could undermine U.S. companies during the holiday shopping season.

Yet on Friday, Beijing announced plans to implement a new round of tariffs on U.S. goods.

“This is incredible language. The word ‘enemy’ really takes this to a new level,” said Bonnie Glaser, a China expert at the Center for Strategic and International Studies. “The Chinese will be quite startled by the fact that the president could even raise the fact that China could be an enemy.”

Trump bashed China in his 2016 campaign, complaining that the communist country had taken advantage of lax trade policies from previous U.S. administrations of both political parties.

But after taking office, Trump courted Xi, playing host to him at his Mar-a-Lago resort in Florida in an effort to engage him on trade negotiations and enlist Beijing’s cooperation on a “maximum pressure” campaign on North Korea.

Xi returned the favor by treating Trump to an elaborate state visit later that year, feting him with a private performance of the Peking Opera and a military procession that impressed the American president. During that trip to Beijing, Trump told a group of American business leaders, “I don’t blame China” for its unfair trade practices, saying he faulted previous U.S. administrations for failing to get tough.

Last year, however, Trump began to shift his tone, criticizing Beijing on a range of issues. He faulted China for failing to crack down on fentanyl that was being smuggled into the illicit U.S. drug market, cited the Chinese military as a reason for directing the Pentagon to create a new “Space Force” and accused Beijing of trying to improperly influence U.S. elections.

His administration labeled China a “strategic competitor” in its national security strategy, a shift from past administrations.

At the same time, Trump has generally refrained from criticizing Xi directly, noting only that their friendship might have been strained by the increasing tariffs over the past several months.

The two leaders met most recently on the sidelines of the Group of 20 summit in Osaka, Japan, in late June, during which Trump announced that trade talks would resume. But there has been no breakthrough since then.

Michael Pillsbury, a China expert at the conservative Hudson Institute who informally advises Trump, said he has detected an “increasing arrogance” among the Chinese delegations in recent months. Though the Chinese economy has struggled amid the trade tensions, Xi has demonstrated a willingness to accept more economic pain that Trump’s team had expected, several analysts said.

“My own recent conversations with the president over the last few days, I’ve noticed an increasing frustration with Xi Jinping,” Pillsbury said.

Trump has denigrated China’s global economic standing and suggested that the relative strength of the U.S. economy has given him the upper hand, even as fear of a recession has alarmed the White House and the president’s 2020 campaign team.

This week, Trump blasted past U.S. administrations as having failed to confront Beijing. “Someone had to do it,” Trump said. “I am the chosen one.”

But Evan Medeiros, a China expert who served on the National Security Council in the Obama administration, said Trump’s efforts to court Xi personally “were never taken seriously by the Chinese and were never a source of leverage.”

“The Chinese have come to the conclusion that Trump is far too mercurial to take seriously. They focus on U.S. actions more than words,” said Medeiros, now an Asian studies professor at Georgetown University.

In recent weeks, the Trump administration agreed to sell $8 billion worth of new F-16 fighter jets to Taiwan, angering Beijing, and the Pentagon said it was exploring deploying new missile systems in Asia to blunt Chinese military threats. The administration also labeled China a currency manipulator.

“The last veneer of a constructive U.S.-China relationship was Trump’s efforts to have a positive personal relationship with Xi,” Medeiros said. “Now that his rhetoric has turned, that may indicate a much more fundamental long-term shift in China policy — at least until Trump leaves office.”