WASHINGTON — Michael Flynn, President Donald Trump’s former national security adviser, plead guilty to one count to lying to the FBI as part of an agreement reached with Special Counsel Robert Mueller in his probe into Russian interference in the 2016 election.

Mueller charged Flynn with “willfully and knowingly” making false statements to the FBI regarding his conversations with Russia’s ambassador, Sergey Kislyak.

Flynn arrived at the federal courthouse in Washington about seven minutes before a scheduled 10:30 a.m. ET plea agreement hearing, where he appeared before U.S. District Judge Rudolph Contreras.

Flynn has agreed to cooperate with Mueller as he looks into possible collusion between Trump’s presidential campaign and Russian interests. Flynn faced other potential criminal charges. The plea agreement calls for a sentence between zero and six months in prison, and a fine of $500 to $9,500. The sentence will have to be approved by the court.

“I recognize that the actions that I acknowledged in court today were wrong, and, through my faith in God, I am working to set things right,” Flynn said in a statement. “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 our country. I accept full responsibility for my actions.”

The one charge of making a false statement stems from a Jan. 24 query from FBI agents on his contact with Kislyak the previous month. According to Mueller’s complaint, Flynn lied when he denied that, in a Dec. 29 conversation, he asked Kislyak to “refrain from escalating the situation” in Russia’s response to the imposition of sanctions by the Obama administration. Flynn also denied that Kislyak told him that Russia would moderate its reaction.

The sanctions were imposed by the Obama administration in response to the conclusion from intelligence agencies that the Russian government was responsible for interfering with the presidential election campaign, including the hacking of the Democratic National Committee and into a phishing attack on John Podesta, Hillary Clinton’s campaign chair.

According to documents that Mueller filed with the court, on Dec. 29, Flynn had contacted an undisclosed senior official of Trump’s transition team to talk about the newly imposed sanctions and what to communicate with the Russian ambassador. They discussed the “impact of those sanctions on the incoming administration’s foreign policy goals.” The transition team member was at Mar-a-Lago at the time along with other transition team members, according to the filing,

They also discussed that other members of Trump’s transition team “did not want Russia to escalate the situation.” After talking to the transition team official, Flynn called the Russian ambassador to make the request. After that conversation, he called the transition team official to report on the substance of the call, including what was said about the sanctions.

Russian President Vladimir Putin issued a statement on Dec. 30 indicating that Russia would not take retaliatory measures in response to the sanctions.

Mueller’s complaint also claims that Flynn lied when he denied that he asked Kislyak on Dec. 22 that Russia should delay a vote on a United Nations Security Council resolution on Israel.

Flynn resigned in February, just weeks into his tenure as national security adviser, after it was revealed that he lied to Vice President Mike Pence about the nature of his contact with Kislyak. He had denied that he had discussed the newly-imposed sanctions with the Russian ambassador, when in fact transcripts of his phone conversations showed that he had, according to the Washington Post, which broke the news.

Flynn also faced other legal troubles. He had failed to disclose that he was lobbying on behalf of the Turkish government, as is required by federal law.

On Oct. 30, Mueller’s team brought charges against Paul Manafort, Trump’s former campaign chairman, and his associate, Rick Gates, on multiple charges including money laundering stemming from their work as lobbyists on behalf of the government of Ukraine. That same day, a legal filing was unsealed that showed that George Papadopoulos, a former foreign policy adviser to Trump’s campaign, plead guilty to making false statements to FBI agents about the extent of his contact with sources connected to the Russian government.

The full complaint against Flynn is here.

Flynn is a retired U.S. Army lieutenant general, who joined Trump’s campaign as an adviser and spoke at the Republican National Convention. He had served as director of the Defense Intelligence Agency during President Barack Obama’s term, but was reportedly forced out after clashing with other defense officials and complaints over his management of the agency. Obama reportedly warned Trump against hiring Flynn in their first meeting at the White House after the election.

Ty Cobb, one of Trump’s lawyers, issued a statement saying, “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.”