WASHINGTON (CN) – Special counsel Robert Mueller’s team asked a federal judge Monday to bar Paul Manafort from using a lack of IRS enforcement actions against him in his defense during his criminal trial in D.C. this September.

Prosecutor Andrew Weissmann made the request in response to statements defense counsel for Manafort reportedly made during opening arguments in a separate criminal trial for bank and tax fraud currently underway in Alexandria, Virginia.

“As you hear all the evidence come in, the documents and the testimony, you might ask yourself whether the Government knew enough to initiate the audit. Did they have enough evidence,” the 5-page Motion quotes defense counsel as having told the jury.

In Washington, D.C., Manafort faces related charges for conspiracy, money laundering, failing to register as a foreign agent and making false statements about his foreign lobbying work to the Justice Department.

Weissmann wants the court to stop Manafort from arguing at trial that the IRS never audited him or his companies, or that the Justice Department never initiated any civil actions against him for Foreign Agent Registration Act violations.

Weissmann also asked the court to prohibit Manafort’s defense team from suggesting that the lack of such civil actions implies a lack of evidence for the crimes he is accused of.

“The availability of a civil remedy is irrelevant to the issue of criminal liability, will serve only to confuse and mislead the jury, and will invite jury nullification,” the motion argues.

In addition, it asks the court to amend a pending motion to prevent Manafort from suggesting that prosecutors “resurrected charges previously investigated but declined for prosecution.”

Also on Monday, the federal judge overseeing Mueller’s prosecution of oligarch-owned Russian firm Concord Management and Consulting approved the use of “firewall” counsel to handle sensitive discovery.

Prosecutors had objected to defense attorneys being able to disclose sensitive materials to others absent court approval because of national security concerns.

When defense attorneys want to share any such materials, U.S. District Judge Dabney Friedrich said they must notify the court-approved firewall counsel. If the firewall counsel has any concerns, it must notify the court.

In June, Friedrich issued a sweeping protective order in the case, barring anyone other than Reed Smith defense attorneys “from accessing, sharing, or discussing sensitive discovery materials” without court approval.

That includes Concord owner and confidante of Russian President Vladimir Putin, Yevgeny Prigozhin, who is a codefendant in the case but has yet to make an appearance.

Friedrich has said the protective order’s restrictions can be revisited later, once a trial date has been set.

Concord faces a single conspiracy charge for its alleged role in funding the troll farms accused of disrupting the 2016 presidential election in favor of Donald Trump.