WASHINGTON (Reuters) - The White House on Friday distanced itself from a news report it embraced a day earlier that Britain’s top-secret eavesdropping agency monitored Trump Tower at former U.S. President Barack Obama’s behest.

U.S. President Barack Obama (R) greets President-elect Donald Trump at inauguration ceremonies swearing in Trump as president on the West front of the U.S. Capitol in Washington, U.S. REUTERS/Carlos Barria

The White House had cited the report by a Fox News analyst as it sought to defend President Donald Trump’s charge that Obama’s administration wiretapped him during the 2016 election. Over the past two weeks, Trump and his aides have pressed the claim in numerous ways, including suggestions that Trump may have been monitored through microwaves and television sets.

The White House has provided no proof to support Trump’s allegation and the heads of U.S. House and Senate intelligence panels, including from Trump’s Republican Party, have rejected it.

Here is a chronology of the administration’s assertions:

MARCH 4: In a series of early morning tweets, Trump accuses Obama of having his wires tapped and calls him a “bad (or sick) guy.” Trump spokesman Sean Spicer says the White House’s top lawyer was examining options for pursuing the claim.

MARCH 5: The White House cites reports of potentially politically motivated investigations, and says Trump wanted the congressional intelligence committees to examine whether executive branch investigative powers were abused in 2016.

MARCH 6: Spicer suggests monitoring may have been broader than a wire tap, might have been conducted under a secret foreign intelligence eavesdropping warrant and that “there is substantial reporting out there from individuals and from sources” that such surveillance occurred.

MARCH 7: Spicer says while there is no new proof of Trump’s allegation, the president has absolutely no regrets about his tweets and that he was “not walking anything back or regretting.”

MARCH 12: Senior White House adviser Kellyanne Conway suggests in an interview with the Bergen County Record newspaper that the monitoring may have been conducted through television sets or “microwaves that turn into cameras.”

MARCH 13: Conway says her comments the previous day were misconstrued but continues to air the allegation about the president and wiretapping at Trump Tower. Spicer says Trump’s charges were based on reporting by a number of news organizations, including Fox, the BBC and the New York Times. Trump’s use of the word “wiretapping ... spans a whole host of surveillance types of options,” Spicer says.

MARCH 14: Spicer says Trump is extremely confident the Justice Department would find evidence proving his allegation.

MARCH 15: Republican and Democratic leaders of the House Intelligence Committee say they have seen no evidence of wiretapping. The White House defends Trump’s allegation, and Trump says in a Fox News interview that, “We will be submitting things before the committee very soon that hasn’t been submitted as of yet. But it’s potentially a very serious situation.”

MARCH 16: The Republican and Democratic leaders of the Senate Intelligence Committee, and House Speaker Paul Ryan, separately say there is no proof of Trump’s charge.

Spicer says there is no question that surveillance techniques were used. He cites a litany of news reports to justify the allegation. They include an assertion by a Fox News analyst, former New Jersey Judge Andrew Napolitano, that he had been told by unidentified intelligence officials that Obama obtained transcripts of Trump’s conversations from Government Communications Headquarters, or GCHQ, the British agency that monitors overseas communications.

MARCH 17: The administration backs away from the Fox News report after the British government said it was assured by the White House that it would not repeat Napolitano’s allegation, dubbed “nonsense” by a GCHQ spokesman.

“Mr. Spicer was simply pointing to public reports, not endorsing any specific story,” said a White House official.