JUST six days into his presidency, Donald Trump was informed his national security adviser had misled his vice president about contacts with Russia. Trump kept his No. 2 in the dark and waited nearly three weeks before ousting the aide, Michael Flynn, citing a slow but steady erosion of trust, White House officials said.

Flynn was interviewed by the FBI about phone calls with Russia’s ambassador to the US, a sign his ties to Russia had caught the attention of law enforcement officials.

But in the White House’s retelling of Flynn’s stunning downfall, his error was not that he discussed US sanctions with the Russian before the inauguration but the fact he denied it for weeks, apparently misleading Vice President Mike Pence and other senior Trump aides about the nature of the conversations.

White House officials said they conducted a thorough review of Flynn’s interactions, including transcripts of calls recorded by US intelligence, but found nothing illegal.

Pence, who had vouched for Flynn in a televised interview, is said to have been angry and deeply frustrated.

Trump lashed out at the news media yesterday, sending out a tweet berating some news organizations for focusing on “This Russian connection non-sense.” Trump also tweeted: “The fake news media is going crazy with their conspiracy theories and blind hatred.” He added that the news reporting was “merely an attempt to cover-up the many mistakes made in Hillary Clinton’s losing campaign.”

Trump also asserted: “Information is being illegally given to the failing @nytimes & @washingtonpost by the intelligence community (NSA and FBI?). Just like Russia.”

At the White House on Tuesday, press secretary Sean Spicer told reporters: “The evolving and eroding level of trust as a result of this situation and a series of other questionable incidents is what led the president to ask General Flynn for his resignation.”

On Monday, Flynn, in an interview with The Daily Caller News Foundation, said “there were no lines crossed” in his conversations with Sergey Kislyak.

The explanation of the episode left many questions unanswered, including why Trump didn’t alert Pence to the matter and why Trump allowed Flynn to keep accessing classified information and taking part in the president’s discussions with world leaders up until the day he resigned.

White House officials also struggled to explain why Trump counselor Kellyanne Conway had declared the president’s “full confidence” in Flynn just hours before the adviser had to submit his letter of resignation.

Later on Tuesday, The New York Times said US agencies had intercepted phone calls last year between Russian intelligence officials and members of Trump’s 2016 campaign team. Current and former US officials who spoke to the Times anonymously said they found no evidence the Trump campaign was working with the Russians on hacking or other efforts to influence the election.

The White House shakeup, less than one month into Trump’s tenure, marked another jarring setback for an administration already dealing with tensions among top aides and a legal fight over the president’s travel ban order. Flynn’s exit also heightened questions about the president’s friendly posture toward Russia. Democrats called for investigations into Flynn’s contacts, and Republican Senator Lindsey Graham said Congress needed to know whether he had been acting with direction from the president or others.

Trump initially thought Flynn could survive the controversy, according to a person with knowledge of the president’s views, but a pair of explosive stories in The Washington Post in recent days made the situation untenable.

As early as last week, he and aides began making contingency plans for Flynn’s departure, a senior administration official said. While the president was said to be upset with Flynn, he also expressed anger with other aides for “losing control” of the story and making his young administration look bad.

Pence spokesman Marc Lotter said Pence became aware that he had received “incomplete information” from Flynn only after the first Washington Post report on Thursday night. Pence learned about the Justice Department warnings to the White House around the same time.

Ahead of the January 20 inauguration, Pence and other officials insisted publicly that Flynn had not discussed sanctions in his talks with Kislyak. On January 26, Acting Attorney General Sally Yates contacted White House counsel Don McGahn to raise concerns about discrepancies between the public account and what intelligence officials knew to be true about the contacts based on routine recordings of communications with foreign officials in the US.

The Justice Department is said to have warned the White House that the inconsistencies would leave the president’s top national security aide vulnerable to blackmail from Russia. The president was informed of the warnings the same day, Spicer said. Flynn was interviewed by the FBI around the same time, a US official said.

McGahn, along with chief of staff Reince Priebus and strategist Steve Bannon, also questioned Flynn multiple times in the ensuing weeks, a White House official said. Top aides also reviewed transcripts of Flynn’s contacts with the ambassador. At the same time, Trump aides began taking steps to put some distance between the president and Flynn. CIA Director Mike Pompeo and retired Lieutenant General Keith Kellogg, a top Flynn aide, started taking part in Trump’s daily briefings.

Top Trump advisers quietly met with Vice Admiral Robert Harward last week and spoke with the former Navy SEAL again on Monday, the White House official said. Harward is seen as the top contender for the job, though former CIA Director David Petraeus and Kellogg, who has temporarily stepped into the role, are also under consideration.

Spicer said other “questionable incidents” had contributed to Flynn’s exit. Those incidents are said to have included Flynn seeking a security clearance for his son during the transition.

At the time, it was Pence who was again put in the position of defending Flynn on television, saying he had not sought a clearance for the son.

A US official told reporters Flynn was in frequent contact with Kislyak on the day the Obama administration slapped sanctions on Russia for election-related hacking, as well as at other times during the transition. Spicer said Flynn was not discussing sanctions at the president’s behest.

Before he resigned, Flynn told the investigative news nonprofit affiliated with website The Daily Caller that he and Kislyak spoke only generally about the Russian diplomats expelled by President Barack Obama as part of the previous administration’s response to Moscow’s interference in the US presidential election.

“I never said anything such as, ‘We’re going to review sanctions,’ or anything like that,” he said.