The special counsel's office pushed back Friday at the suggestion that the FBI acted improperly in its interview of former national security adviser Michael Flynn, saying he agreed on his own to meet with federal agents and did not need a warning that it was against the law to lie to them.The filing from special counsel Robert Mueller comes four days before Flynn gets sentenced on a charge of lying to the FBI about his conversations with the then-Russian ambassador to the United States. It responds to a sentencing memorandum filed earlier this week by Flynn's lawyers that said the FBI did not warn him that it illegal to lie. It also suggested that agents discouraged him from having a lawyer present.But prosecutors with Mueller's office rejected those arguments.They said Flynn had lied several times to White House officials about his dialogue with ambassador Sergey Kislyak and simply repeated those falsehoods when approached by the FBI on Jan. 24, 2017. They said Flynn agreed to meet with the FBI without a lawyer present and, unlike other defendants charged in Mueller's investigation, had enough experience in government to understand the consequences of lying and "the importance of accurate information to decision making in areas of national security.""A sitting National Security Advisor, 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," Mueller's prosecutors wrote. "He does not need to be warned it is a crime to lie to federal agents to know the importance of telling them the truth."Flynn's supporters have seized on the fact that the FBI agents who questioned him did not detect signs of deception during the interview. But prosecutors say that doesn't change the fact "that he was indeed lying, and knowingly made false statements to FBI agents in a national security investigation."Neither prosecutors nor defense lawyers are seeking prison time for Flynn at his sentencing Tuesday.