WASHINGTON — Dogged by signs that prosecutors are zeroing in on his inner circle, President Donald Trump insisted Saturday that he wasn’t worried about what his former national security adviser, Michael Flynn, may tell investigators after agreeing to a plea deal Friday.

“What has been shown is no collusion, no collusion,” Trump told reporters as he left the White House for a series of fundraising events in New York City.

In a tweet, Trump said he “had to fire” Flynn because the retired Army lieutenant general lied to Vice President Mike Pence and the FBI about contacts with Russia’s then-ambassador in Washington, Sergey Kislyak.

Flynn pleaded guilty Friday to lying to the FBI about his conversations in December with Kislyak.

Trump wrote it’s a “shame” Flynn lied because “his actions during the transition were lawful,” adding: “There was nothing to hide!”

It was the first time Trump said publicly that Flynn’s firing was related to his lying to the FBI. White House officials previously said Flynn was fired because he misrepresented his conversations with Kisylak to Pence.

Trump’s tweet may indicate he knew Flynn was in legal jeopardy for lying to the FBI when, the day after firing Flynn, Trump reportedly asked then-FBI Director James Comey whether he could see his way “to letting Flynn go.” Comey wrote down Trump’s comments in notes he made after the Feb. 14 meeting.

Trump’s admission may bolster a case that Trump was obstructing justice by asking Comey to intervene in Flynn’s case. Trump fired Comey in May.

Legal experts have speculated that Flynn may have pushed the limits of the Logan Act, which prohibits private citizens from interfering in U.S. foreign policy, when he allegedly made assurances to Kislyak during the transition before Trump took office.

Special counsel Robert Mueller is investigating whether Trump’s campaign colluded or coordinated with Russia during the 2016 election.

“There’s been absolutely no collusion, so we’re very happy. And frankly last night was one of the big nights,” Trump said, referring to the narrow passage of the Republican tax bill out of the Senate.

After passing by a vote of 51-49 following an early-morning scramble, the Senate’s tax bill is to go Monday to a conference committee, where GOP lawmakers from the House and Senate will hammer out differences in their versions of the legislation in an effort to get a final bill on Trump’s desk before Christmas.

Republicans feel they need to pass the bill soon in order to boost GOP congressional and Senate campaigns in the run-up to the 2018 midterm elections.

The bill includes cuts to corporate tax rates, the end to many personal tax deductions and an overhaul of the estate tax. Sen. Bob Corker of Tennessee was the only Republican to vote against the bill, over concerns it would increase budget deficits. The tax package, which passed with no Democratic votes, is projected to add $1 trillion to the deficit over 10 years, despite GOP pledges that economic growth spurred by tax cuts will pay for the reductions in revenue.

“Now we go onto conference and something beautiful is going to come out of that mixer. People are going to be very, very happy. They’re going to get tremendous, tremendous tax cuts and tax relief, and that’s what this country needs,” he said.

Trump, who often lashes out at those who go against him, refrained in two early-morning tweets Saturday from attacking Corker, whom he has repeatedly mocked in the past.

Senate Democrats pilloried GOP leaders for passing such a sweeping bill with last-minute additions handwritten in the margins.

“Any handwriting experts out there?” Sen. Bob Casey Jr., D-Pa., wrote on Twitter along with a photo of handwriting on the edge of the bill. “This is absurd.”

In one late change, Senate Republicans dropped plans to eliminate the so-called alternative minimum tax for individuals.

brian.bennett@latimes.com