President Trump and German Chancellor Angela Merkel participate in a joint news conference in the East Room of the White House on Friday. (Jabin Botsford/The Washington Post)

President Trump’s unproven allegation that his predecessor wiretapped Trump Tower in New York ahead of the election blazed a new path of political disruption Friday as he dragged two foreign allies into his increasingly thin argument that he is right.

Standing next to German Chancellor Angela Merkel at a White House news conference Friday afternoon, Trump declined to express regret for the accusation he tweeted nearly two weeks ago, despite some of the highest-ranking members of his own party saying they have seen no evidence that any such wiretapping occurred. Trump also passed on the opportunity to reject an unfounded report from a Fox News commentator asserting that British intelligence agents were involved in the alleged spying — even though White House officials had just assured livid British leaders that they would no longer promote the claim.

“As far as wiretapping, I guess by this past administration, at least we have something in common, perhaps,” Trump said to Merkel, referring to reports that the National Security Agency had tapped the chancellor’s phone in 2010 under President Barack Obama.

Merkel did not respond to Trump’s attempt at a joke.

The international incidents cap nearly two weeks of surreal debate over the president’s apparently baseless accusation that Obama personally ordered the wiretapping of his Trump Tower campaign headquarters, consuming the time of not only White House staffers but also Congress, the Justice Department, the CIA and other intelligence agencies.

(Bastien Inzaurralde/The Washington Post)

[Trump’s news conference with Merkel, in four minutes]

In the days since Trump’s tweets alleging the wiretapping were posted, the White House has called for a congressional investigation, declined to comment, dodged questions, pointed to media reports that don’t contain the information aides say they do and analyzed the president’s use of quotation marks — all while doubling down on his claim without providing any evidence.

As aides jumped to defend their boss, they often seemed to invent evidence as they went. In one instance this week, counselor Kellyanne Conway said televisions or microwaves could have been used as surveillance cameras in Trump Tower — a comment she later said was a joke.

In recent days, Trump and his press secretary, Sean Spicer, have said the president’s allegations referred to broader surveillance efforts — and not wiretapping specifically — but they otherwise did not back off the initial claim.

Meanwhile, an Obama spokesman and several members of the Obama administration have publicly denied the accusation, and FBI Director James B. Comey reportedly urged the Justice Department to dispute it. In Congress, House Speaker Paul D. Ryan (R-Wis.) and other prominent leaders — including all four top-ranking members of the two intelligence committees — announced this week they had no evidence that Trump Tower was wiretapped.

[House intelligence panel does not reveal whether documents substantiate Trump’s claim]

Wiretaps in a foreign intelligence probe cannot legally be directed at a U.S. facility without probable cause — reviewed by a federal judge — that the phone lines or Internet addresses at the facility are being used by agents of a foreign power or by someone spying for or acting on behalf of a foreign government. Furthermore, no president can legally order such a wiretap.

(Reuters)

Rep. Tom Cole (R-Okla.), who has been a strong Trump supporter, told reporters Friday that the president owes Obama an apology. “It’s not a charge that I would have ever made,” Cole said. “And frankly, unless you can produce some pretty compelling proof, then I think the president, you know, President Obama is owed an apology in that regard. . . . If he didn’t do it, we shouldn’t be reckless in accusations that he did.”

Trump has been feuding with the intelligence community since before he took office, convinced that career officers as well as holdovers from the Obama administration have been trying to sabotage his presidency. He has ordered internal inquiries to find who leaked sensitive information regarding communications during the campaign between Russian officials and his campaign associates and allies.

The controversy is scheduled to continue into a third week, with Comey set to testify Monday before the House Intelligence Committee. He has been asked to clarify whether the FBI is investigating Russia’s role in the 2016 election and alleged links between the Trump team and Russian officials.

On Friday, the House Intelligence Committee received a set of documents from the Justice Department in response to its request for materials regarding Trump’s accusation. The panel did not reveal whether the documents substantiate or refute the president’s wiretapping claims.

[Inside Trump’s fury: The president rages at leaks, setbacks and accusations]

Committee Chairman Devin Nunes (R-Calif.) and ranking Democrat Adam B. Schiff (Calif.) originally asked the Justice Department to send copies of any wiretapping warrants, applications, court orders or other proof of Trump’s allegations by last Monday. But the lawmakers extended the deadline at the administration’s request. Many lawmakers have expressed skepticism that such wiretaps existed.

The uproar began early March 4, when Trump — angry over the decision by Attorney General Jeff Sessions to recuse himself from probes related to Russia and the election — went on a tear on Twitter from his Mar-a-Lago estate in Florida, firing off four tweets accusing Obama of a plot to “tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!”

Earlier this week, Spicer again attempted to buttress Trump’s claim by reading aloud a report from Andrew Napolitano, a former New Jersey Superior Court judge and a regular commentator for Fox News. Napolitano claimed on air that three intelligence sources had said that Obama “went outside the chain of command” and used Britain’s main surveillance agency to spy on Trump so “there’s no American fingerprints on this.”

Spicer’s quoting of the flimsy claim angered British officials, and a spokesman for Prime Minister Theresa May said at a news briefing Friday — before Trump’s news conference in Washington — that they had “received assurances from the White House that these allegations would not be repeated.”

The Government Communications Headquarters, the British equivalent of the NSA, is usually tight-lipped on allegations related to intelligence matters, but it issued a statement calling Napolitano’s accusations “nonsense.”

“They are utterly ridiculous and should be ignored,” the statement said.

[Britain: White House says it won’t repeat claims that British agency wiretapped Trump]

Many foreign policy experts have expressed growing alarm about the Trump presidency and its relationship with European allies.

“On two major relationships, both Britain and Germany, you’ve got this unease that something’s not right,” said Julie Smith, a onetime deputy national security adviser to former vice president Joe Biden. “. . . These are, frankly, fairly dark days in the transatlantic relationship.”

A senior White House official said Friday that British concerns about the claim were relayed to Spicer by British Ambassador Kim Darroch and to national security adviser H.R. McMaster by his British counterpart, Mark Lyall.

When given the opportunity Friday to publicly refute the unfounded report, Trump passed.

“We said nothing,” Trump said at his news conference. “All we did was quote a certain very talented legal mind who was the one responsible for that on television. I didn’t make an opinion on it. That was a statement made by a very talented lawyer on Fox.

“So you shouldn’t be talking to me, you should be talking to Fox,” the president added.

After the news conference, Fox News issued an on-air statement delivered by anchor Shepard Smith saying that it could not confirm Napolitano’s commentary: “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.”

But the White House still did not retreat.

“I don’t think we regret anything,” Spicer told reporters in the East Room after the joint news conference. “We literally listed a litany of media reports that were in the public domain.”

Adam reported from London. Rick Noack in London and Abby Phillip, Philip Rucker, Karoun Demirjian and John Wagner in Washington contributed to this report.