NEW YORK (CBSNEwYork/CBSNews/AP) — Former national security advisor Michael Flynn pleaded guilty Friday to lying to the FBI.

Flynn is now the first official that worked in the Trump White House to enter a guilty plea in special counsel Robert Mueller’s investigation into possible coordination between Russia and the Trump campaign to influence the 2016 election.

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According to court documents filed by Mueller, the 58-year-old retired three-star Army lieutenant general “…did willfully and knowingly make materially false, fictitious, and fraudulent statements…” to agents about his conversations with Russian Ambassador Sergey Kislyak in January.

Flynn was forced out of the Trump Administration in February for misleading Vice President Pence about those conversations.

EXTRA: Read The Complaint (.pdf) |Read The Plea Agreement (.pdf) | Michael Flynn Statement Of Offense

As part of the plea deal, Flynn admitted that a senior member of the Trump transition team directed him to contact Russian officials in December 2016.

The government did not reveal the identity of the senior transition official. 

Three sources with knowledge of the situation tell CBS News top White House aide and President Donald Trump’s son-in-law Jared Kushner was the “very senior” official who first directed Flynn to contact Russian officials and urge them to delay or defeat a United Nations resolution on Israeli settlements.

“On or about December 22, 2016, a very senior member of the Presidential Transition Team directed FLYNN to contact officials from foreign governments, including Russia, to learn where each government stood on the resolution and to influence those governments to delay the vote or defeat the resolution,” the statement of offense against Flynn reads.

gettyimages 883624290 Kushner Told Flynn To Contact Russian Officials, Sources Tell CBS News

Michael Flynn, former national security advisor to President Donald Trump, arrives for his plea hearing at the Prettyman Federal Courthouse December 1, 2017 in Washington, DC. (Photo by Chip Somodevilla/Getty Images)

Three sources also tell CBS News that K.T. McFarland was the other “senior official” who spoke with Flynn at Mar-a-Lago on December 29 about sanctions the Obama administration imposed on Russia.

Following their conversation, Flynn relayed to Kislyak the Trump team did not want Russia to escalate the situation, according to court documents.

Russian President Vladimir Putin later announced he would not retaliate for the sanctions, and President-elect Trump tweeted that Putin was very smart, CBS2’s Dick Brennan reported.

“On or about Decmber 31, 2016, the Russian Ambassador called Flynn and informed him that Russia had chosen not to retaliate in response to Flynn’s request,” court documents read.

The lack of a response from the Russia to sanctions imposed by the Obama Administration stunned intelligence officials working in the previous administration.  In an interview earlier this year, former Director of National Intelligence James Clapper told CBS that the reaction was “very un-Russian-like” and “curious.” 

White House lawyer Ty Cobb said, “Nothing about the guilty plea or the charge implicates anyone other than Mr. Flynn. The conclusion of this phase of the Special Counsel’s work demonstrates again that the Special Counsel is moving with all deliberate speed and clears the way for a prompt and reasonable conclusion.”

Trump did not respond to shouted questions from reporters Friday morning as he welcomed Libyan Prime Minister Fayez Serraj to the White House. He waved and flashed a thumbs up.

In a statement, Flynn said:

“After over 33 years of military service to our country, including nearly five years in combat away from my family, and then my decision to continue to serve the United States, it has been extraordinarily painful to endure these many months of false accusations of “treason” and other outrageous acts. Such false accusations are contrary to everything I have ever done and stood for. But I recognize that the actions I acknowledged in court today were wrong, and, through my faith in God, I am working to set things right. My guilty plea and agreement to cooperate with the Special Counsel’s Office reflect a decision I made in the best interests of my family and of our country. I accept full responsibility for my actions.”

Flynn has been released with bail. A sentencing date has not been set.

Flynn is the fourth person charged in connection with Mueller’s investigation.

Back in October, prosecutors charged Trump’s former campaign chairman Paul Manafort, his deputy Rick Gates, and campaign adviser George Papadopoulos as part of the probe.

Last week Flynn’s attorney, Robert Kelner, called Donald Trump lawyer John Dowd to inform him they could no longer communicate about Flynn, at the time thought to be a possible sign that Flynn is ready to cooperate with the investigation.

Trump’s legal team has been expecting this development for weeks. They have been awaiting either an indictment of Flynn or his son, or a plea deal involving one of both.

Flynn had a security clearance during Mr. Trump’s campaign and the subsequent transition to the White House as a result of his service as head of the Defense Intelligence Agency. Former President Obama fired Flynn from that position in 2014, but he retained the clearance.

Where does the investigation go from here?

“It signals it’s going forward and it’s moving and advancing very quickly,” said former federal prosecutor Peter Zeidenberg. “If anyone was going to be interacting with the Russians or would know about it, it would be Flynn. So if you could get him to talk, it would be worth giving him a great deal.”

Flynn’s plea deal with the special counsel’s office requires him to cooperate with the investigation. He faces a likely sentence of zero to six months in prison, Brennan reported.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)

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