WASHINGTON — Lawyers for Michael T. Flynn, the president’s first national security adviser, escalated their attacks on prosecutors on Friday, recycling unfounded conspiratorial accusations in a last-ditch bid to delay his sentencing in a case in which he has twice admitted guilt.

The move could anger Emmet G. Sullivan, the federal judge who will sentence Mr. Flynn. The filings could magnify any doubts by Judge Sullivan about whether Mr. Flynn truly accepts responsibility for his crime of lying to the F.B.I. and whether he fulfilled his cooperation agreement with the government in one of the lingering cases brought by the special counsel, Robert S. Mueller III.

[Update: Attorney General William Barr installs an outside prosecutor to review the case against Michael Flynn.]

In a pair of filings, Mr. Flynn’s lawyers made clear that they view him as a victim of prosecutorial misconduct, amplifying right-wing theories about a so-called deep state of government bureaucrats working to undermine President Trump. The defense lawyers accused prosecutors of engaging in “pernicious” conduct in Mr. Flynn’s case, saying they had been “manipulating or controlling the press to their advantage to extort that plea.”