Lavrov explains reasons behind Maria Butina's plea deal

The 30-year-old Butina was indicted in July on charges of conspiracy and acting as a foreign agent.

She faces up to five years in prison, and could be deported at any time after her sentencing. She will, however, remain in custody until the sentence is decided at a hearing on February 12, 2019.

In an interview with CNN, foreign ministry spokeswoman Maria Zakharova said Ms Butina had been "tortured" in detention - without providing any evidence - and that the Russian government considered her a "political prisoner".

Butina's arrest was a result of a Justice Department investigation disconnected from that of special counsel Robert Mueller.

The charges against Butina were brought by federal prosecutors in Washington, not Mr. Mueller.

In the statement of offense read aloud in court, one of the prosecutors said Butina had drafted a "Diplomacy Project" that called for establishing unofficial back channels of communication between high-ranking American politicians to help benefit Russian Federation.

Castro said the cooperation of Russian Maria Butina with federal investigators "really opens up an avenue for prosecutors to find out a few things".

He explained that Russian diplomats had visited Butina yesterday. "Butina was aware", the filing said, that Torshin was at times acting at those Russian officials' direction.

But she is the first Russian to be convicted of attempting to sway United States policy in a time period that includes Donald Trump's 2016 presidential campaign.

The Russian Foreign Ministry said earlier Thursday that any decision Butina took to help free her from detention in the US would be supported by Russia.

Russian Foreign Minister Sergey Lavrov told Russian news agencies on Friday that he "understands" why Butina pleaded guilty, quoting what he described as "torturous" prison conditions. She pleaded guilty Thursday to a conspiracy charge in federal court in Washington. Person One helped advise Butina on which American politicians she should target for meetings, and her plan was carried out on behalf of the Russian official, the statement said. "He has done nothing to harm our country and never would". Butina faces possible deportation to Russian Federation after finishing her sentence.

The "Diplomacy Project" document was crafted by Butina with help from Person 1, prosecutors said.

At a town-hall-style event in Las Vegas in 2015, Butina asked candidate Trump whether he would improve the US relationship with Russian Federation.

Butina ran much of her infiltration campaign while studying at a master's program at American University, appearing at NRA events and asking a question of then-candidate Donald Trump in a now-infamous video. Butina also attended Walker's announcement that he was running for president.

USA authorities arrested Butina in mid-July.

Erickson issued a statement on Tuesday through his lawyer Bill Hurd to deny that he has ever done anything to hurt America. Erickson introduced Torshin as an emissary for Vladimir Putin and sought to arrange a meeting with Trump.