The Russiagate probe has it all, from dark plots and dirty doings to, well, a certain sexy selfie now at the centre of an ongoing court showdown.

US Special counsel Robert Mueller has got his hands on what is described as a “nude selfie” while collecting a cache of data from a Russian company charged with interfering in the 2016 presidential election, according to a court filing.

Concord Management and Consulting, which is accused of co-ordinating a massive social media plot to help elect US President Donald Trump, laments in recently filed court papers that the special counsel is overstepping his authority by refusing to release some of the data his team has obtained.

Mueller argues the data should be sealed because it contains “sensitive” information about national security and US intelligence techniques.

Lawyers for Concord begged to differ, scoffing that a nude picture of an unnamed individual hardly represents a threat to national security.

“Could the manner in which he collected a nude selfie really threaten the national security of the United States?” the lawyers asked in the filing.

It was not clear from the filing who is portrayed in the selfie and the exotic revelation wasn’t referenced at any other point in the papers.

A spokesman for the special counsel declined to comment.

The company has been a thorn in Mueller’s paw since the indictments were handed down by sending its US lawyers to court to contest the charges on the grounds that it did not even exist at the time probers charge it was part of a Russian bid to keep Hillary Clinton out of the White House.

It is the only Russian defendant to actually appear in a US court and has pleaded not guilty to a conspiracy charge related to the Kremlin’s sweeping interference in the election.

Taken by surprise, Mueller’s team asked for an immediate adjournment, making the remarkable argument that its own prosecutors had not properly served the required papers on the company.

Since then Astoria has relentlessly ridiculed Mueller and his investigators, with the naked selfie contretemps representing the latest chapter in a legal defence based largely on sarcasm.

The company is owned and operated by Yevgeny Prigozhin, a billionaire oligarch who’s been nicknamed “Putin’s chef” because of his closeness with the Russian president.

Prigozhin, 57, has been separately indicted by Mueller with bankrolling the so-called Internet Research Agency, the Kremlin’s primary troll farm, which launched a multifaceted interference campaign to boost Trump’s chances and disparage Mrs Clinton.

Mueller continues to investigate whether the Trump campaign colluded with any Russians before the election.

His inquiry has produced dozens of indictments against Trump associates and Russian nationals, including the president’s former campaign chairman, national security adviser and personal lawyer.

-with AAP