WASHINGTON – Russia special counsel Robert Mueller Friday rejected any notion that former Trump administration national security adviser Michael Flynn was tricked by FBI agents into lying about his communications with Russian ambassador Sergey Kislyak, resulting in his prosecution.

"The interview was voluntary, and lacked any indicia of coercion," Mueller's prosecutors asserted in new court documents, referring to the Jan. 24, 2017 interview at the White House just days after President Donald Trump's inauguration.

The new filings come after Flynn's attorneys suggested earlier this week that the FBI duped the former national security adviser by not warning him about the criminal consequences for lying to agents during the interview in which Flynn has now acknowledged falsely denying that his conversation with Kislyak included a discussion of Russia sanctions.

"A sitting national security adviser, former head of an intelligence agency, retired lieutenant general and 33-year veteran of the armed forces knows he should not lie to federal agents," prosecutors said.

"The court should reject the defendant's attempt to minimize the serious of those false statements to the FBI."

The new filings come in advance of Flynn's Dec. 18 sentencing. Prosecutors have recommended no prison time for the former Trump administration official who they said has provided substantial cooperation in the ongoing Russia investigation. Flynn's attorneys also have asked that he be spared prison time.

Before the interview, FBI officials had decided that they would not warn Flynn about the potential criminal jeopardy he faced for making false statements.

The interview, according to court documents, had been arranged by then-Deputy FBI Director Andrew McCabe, who was subsequently fired for unauthorized disclosures to reporters. The primary interviewing agent was Peter Strzok, a senior counterintelligence official who was later dismissed for making disparaging comments about candidate Donald Trump in text messages exchanged with an FBI lawyer who was Strzok's girlfriend.

"Even when circumstances later came to light that prompted extensive public debate about the investigation of General Flynn, including revelations that certain FBI officials involved in the Jan. 24 interview of General Flynn were themselves being investigated for misconduct, General Flynn did not back away from accepting responsibility for his actions," Flynn's attorneys said.

Mueller's prosecutors, however, noted that in the weeks before the FBI interview Flynn had also lied about his discussions with the Russian ambassador to reporters, Vice President Mike Pence and members of the president's transition team.

During the interview, according notes of an FBI interview with Strzok, the agent reported that Flynn appeared "unguarded and clearly saw the FBI agents as allies."

"Flynn was so talkative, and had so much time for them, that Strzok wondered if the national security adviser did not have more important things to do than have such a relaxed, non-pertinent discussion with them," according to the FBI notes. At various times, according to Strzok's recollection of the encounter, Flynn "talked about various subjects, including hotels where they stayed during the (presidential) campaign and the president's knack for interior design."

"Throughout the interview, Flynn had a very 'sure' demeanor and did not give any indicators of deception," Strzok told agents.

Despite the questions raised about FBI tactics, prosecutors continued to support leniency for the former administration officer, who will be the first former White House official to be sentenced in Mueller's continuing inquiry.

Last week, Mueller's prosecutors provided an account of Flynn's extensive cooperation, citing the former three-star general's "substantial" assistance to the Russia inquiry and at least two other undisclosed investigations in recommending that he serve no prison time.

Flynn, according to prosecutors, has met with investigators 19 times since he pleaded guilty last year to lying to the FBI about his contacts with Kislyak during the run-up to Trump's inauguration.

Prosecutors have lauded Flynn's assistance, claiming that his early guilty plea and decision to cooperate "likely affected the decisions of related firsthand witnesses to be forthcoming with the (special counsel’s office) and cooperate.”

More:Michael Flynn re-emerges as major witness in Robert Mueller's inquiry – and at least two others

More:Mueller probe: Michael Flynn has offered 'substantial' assistance to investigation; no prison time recommended

"The defendant’s record of military and public service distinguish him from every other person who has been charged as part the (special counsel's) investigation," prosecutors said. "However, senior government leaders should be held to the highest standards. The defendant’s extensive government service should have made him particularly aware of the harm caused by providing false information to the government, as well as the rules governing work performed on behalf of a foreign government."

Flynn, who memorably called for the jailing of Democrat Hillary Clinton during the 2016 Republican convention, discussed U.S. sanctions with Kislyak on Trump’s behalf during the presidential transition and said members of the president’s inner circle were aware of, and in some cases directing, his efforts, according to the plea.

Flynn had urged Kislyak not to respond to sanctions imposed by the Obama administration in response to Russian election interference.

Flynn’s FBI interview came just weeks before he was forced to resign in February 2017. The White House said he was fired for misleading Pence and other senior officials about the content of his conversations with Kislyak.

As part of his plea, Flynn also admitted to lying about Turkish lobbying and research work. He belatedly registered with the Justice Department as a foreign agent for the work weeks after he left the White House.