US President Donald Trump's former campaign manager Paul Manafort sued Special Counsel Robert Mueller, alleging that his office's wide-ranging investigation into possible collusion between the Trump campaign and Russia exceeded its legal authority and needed to be reined in.
Mr Manafort's civil lawsuit, filed in US District Court for the District of Columbia, named both Mr Mueller and Deputy Attorney General Rod Rosenstein, who appointed Mueller in May and is tasked with overseeing the special counsel's operations.
It accused Mr Rosenstein of exceeding his legal authority to "grant Mr Mueller carte blanche to investigate and pursue criminal charges in connection with anything he stumbles across."
Mr Manafort and his business partner Rick Gates were indicted in October by Mr Mueller's office on charges including conspiracy to launder money, conspiracy against the United States and failing to register as foreign agents of Ukraines former pro-Russian government.
The indictment did not make reference to any activity related to Mr Manafort's work on the Trump 2016 presidential campaign.
The lawsuit asked the court to have the case against Mr Manafort dismissed.
A spokeswoman for the Justice Department called the lawsuit "frivolous," but added that Mr Manafort was "entitled to file whatever he wants."
A spokesman for Mr Mueller's office declined to comment.
Mr Rosenstein appointed Mr Mueller in May, shortly after Mr Trump fired former FBI Director James Comey.
Mr Comey has since said he believes he was fired because the US President wanted to undermine the investigation into possible collusion between the campaign and Russia.
Mr Trump has denied that his campaign colluded with Russia, although he has also said he fired Mr Comey because of "this Russia thing."
Moscow has denied meddling in the 2016 US election campaign.
Mr Rosenstein is in charge of overseeing Mr Mueller's operations because Attorney General Jeff Session is recused from the Russia investigation.
Under the terms of Rosenstein's order appointing Mr Mueller, the special prosecutor can not only probe links or coordination between Mr Trump's campaign and Russia, but look into "any matters that arose or may arise directly" from the investigation.
Mr Manafort's attorneys argued that Mr Rosenstein's order cast too wide a net for Mr Mueller's probe.
"The investigation has focused on Manafort's offshore business dealings that date back to as early as 2005-about a decade before the Trump presidential campaign launched," the lawsuit said.
It also alleged that the appointment order by Rosenstein was "arbitrary" and "capricious" and needed to be set aside.