

WASHINGTON — President Trump provoked a rare public dispute with the United States’ closest ally on Friday after his White House aired an explosive and unsubstantiated claim that Britain’s spy agency had secretly eavesdropped on him at the behest of President Barack Obama during last year’s campaign.
Livid British officials adamantly denied the allegation and secured promises from senior White House officials never to repeat it. But a defiant Trump refused to back down, making clear that the White House had nothing to retract or apologize for because his spokesman had simply repeated an assertion made by a Fox News commentator. Fox itself later disavowed the report.
The rupture with London was Trump’s latest quarrel with an ally or foreign power in the two months since taking office. Mexico’s president angrily canceled a White House visit in January after Trump insisted that the United States’ southern neighbor pay for a border wall. A telephone call between the president and Australia’s prime minister then ended abruptly amid a dispute over refugees. And China refused for weeks to engage with Trump because of his postelection call with Taiwan’s president.
Trump’s strained relations with Europe, which has viewed his ascension to power with trepidation, were fully on display Friday, not just in the British spy flap but also in the venue in which it was addressed. The president was hosting for the first time Chancellor Angela Merkel of Germany, who is seen by many Europeans as the most important champion of the liberal international order.
Though polite, the two leaders seemed stiff and distant during their public appearances. European news outlets and social media made much of the fact that she suggested a handshake for photographers in the Oval Office and he did not respond, although it appeared that he did not hear her. Either way, the two were clearly on separate pages on issues like immigration and trade.
The angry response from Britain stemmed from Trump’s persistence in accusing Obama of tapping his phones last year despite the lack of evidence and across-the-board denials. At a briefing Thursday, Sean Spicer, the White House press secretary, read from a sheaf of news clippings that he suggested bolstered the president’s claim.
Among them was an assertion by Andrew Napolitano, a Fox News commentator, that Obama had used Britain’s Government Communications Headquarters, the signals agency known as the GCHQ, to spy on Trump. In response to Spicer, the agency quickly denied it as “nonsense’’ and “utterly ridiculous,’’ while British officials contacted American counterparts to complain.
“We said nothing,’’ Trump told a German reporter who asked about the matter at a news conference with Merkel. “All we did was quote a certain very talented legal mind who was the one responsible for saying that on television. I didn’t make an opinion on it.’’ He added: “You shouldn’t be talking to me. You should be talking to Fox.’’
The president tried making a joke about it, turning to Merkel, who was angered during Obama’s administration by reports that the National Security Agency had tapped her cellphone and those of other leaders. “At least we have something in common, perhaps,’’ Trump said. She made a face that suggested she had no interest in getting involved.
After the news conference, Spicer echoed Trump’s unapologetic tone. “I don’t think we regret anything,’’ he told reporters. “As the president said, I was just reading off media reports.’’
Shortly afterward, Fox backed off Napolitano’s claim. “Fox News cannot confirm Judge Napolitano’s commentary,’’ anchor Shepard Smith said on air. “Fox News knows of no evidence of any kind that the now president of the United States was surveilled at any time, any way. Full stop.’’
Trump’s unremorseful tenor further stunned British officials, who thought they had managed to contain the matter. Kim Darroch, the British ambassador to the United States, had raised the matter Thursday night with Spicer at a St. Patrick’s Day reception in Washington. Mark Lyall Grant, the national security adviser to Prime Minister Theresa May of Britain, had contacted his American counterpart, Lieutenant General H.R. McMaster.
On Friday morning, a spokesman for May said the White House had backed off the allegation. “We’ve made clear to the administration that these claims are ridiculous and should be ignored,’’ the spokesman said, on the condition of anonymity in keeping with British protocol. “We’ve received assurances these allegations won’t be repeated.’’
But White House officials, who also requested anonymity, said Spicer had offered no regret to the ambassador. “He didn’t apologize, no way, no how,’’ a senior West Wing official said. The officials said they did not know whether McMaster had apologized.
The furor underscored the continuing troubles for the White House since Trump first accused Obama of tapping his phones, an allegation refuted by intelligence agencies as well as Republican and Democratic officials. Even as Trump refused to back down, fellow Republicans appeared increasingly irritated by what they see as a distraction from their policy goals.
Julianne Smith, who was a deputy national security adviser to Vice President Joe Biden, said it appeared that Trump did not realize how much US intelligence agencies depend on Britain in dealing with threats around the world. “He will probably live to the day when he will regret firing off such an egregious insult to Britain and then failing to apologize for it,’’ she said.
The issue touched a nerve at GCHQ, which usually refuses to comment on intelligence matters. Its vehement response surprised British officials and analysts.
Tim Farron, the leader of the Liberal Democrats, the junior partner in the last British coalition government, described Spicer’s repetition of the claims as “shameful’’ and said Trump was “compromising the vital UK-US security relationship to try to cover his own embarrassment.’’