Image copyrightFacebook/ Maria Butina

A Russian woman accused of trying to influence US politics as a spy for Russia will appear before a federal judge in Washington DC on Wednesday.

Maria Butina allegedly courted Republican-backed groups, such as the National Rifle Association, under the direction of a senior Russian official.

A lawyer for the 29-year-old said she has been co-operating with the US government for several months.

The case is not part of the US inquiry into alleged Russian election meddling.

She is scheduled to appear before a US magistrate judge one day after she was formally indicted on charges of failing to register as a foreign agent and conspiring against the US government.

On Wednesday, Moscow's foreign ministry said Ms Butina's arrest was designed to undermine the "positive results" of a summit between US President Donald Trump and Russian President Vladimir Putin in Helsinki on Monday.

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Her lawyer, Robert Driscoll, has denied FBI claims the recent graduate of American University in Washington DC is an "an agent of the Russian Federation".

"There is simply no indication of Butina seeking to influence or undermine any specific policy or law (of) the United States - only at most to promote a better relationship between the two nations," Mr Driscoll said in a statement after her arrest on Sunday.

'An agent of influence'

The Department of Justice alleges that Ms Butina worked "under the direction and control" of a senior Russian official who is not named in charging documents.

But according to US media, the Russian official appears to be Alexander Torshin, a well-connected Russian senator from President Vladimir Putin's political party.

Court papers say the Russian official acted as her spy handler, and coached her through online messages to win "the battle for the future" and "not burn out (fall) prematurely".

"Only incognito!" Ms Butina allegedly replied through a private Twitter message one month before the 2016 presidential election.

"Right now everything has to be quiet and careful."

On the night of the presidential election in 2016, court filing say she messaged Mr Torshin: "I'm going to sleep. It's 3 a.m. here."

"I am ready for further orders."

Siberian gun campaigner

People who met Ms Butina said she was a charismatic and gregarious flame-haired Russian whose colourful life story appealed to conservatives she met at events around the US.

In 2015 she told a US radio show that she grew up in the woods of Siberia, and was taught to hunt by her father.

After a brief career as the owner of a chain of furniture stores, she said she moved to Moscow where she founded a group called the Right to Bear Arms, which supposedly advocates for private gun ownership in Russia.

On her F-1 student visa application when she entered the US in August 2016, Ms Butina said she had previously been employed as special assistant to Mr Torshin.

Mr Torshin is a lifetime member of the National Rifle Association (NRA) - a powerful US lobbying organisation that supports gun rights and pro-gun politicians.

During her time in the US, she began to foster her own relationships with conservative pro-gun groups.

He has also brought Christian conservatives to Russia for an annual prayer breakfast that he hosts.

That is how Ms Butina came to meet a Republican political operative who is alleged to have helped introduce her to politically influential people in the US.

Sources tell US media that the fact that Mr Torshin was not charged is a sign investigators are working to secure her co-operation against Mr Torshin and possibly other Russian officials.

At one point during the presidential election, she and the official allegedly tried unsuccessfully to broker a meeting between Mr Trump and Mr Putin.

Relationship with Republican operative

Ms Butina testified to the Senate Intelligence Committee in April, her lawyer said - the same month that the US Department of Treasury imposed financial sanctions on Mr Torshin.

According to US media, Ms Butina told the Senate committee she had begun a romantic relationship with Paul Erickson, a well-known South Dakota-based Republican operative.

Mr Erickson is presumed to be the unnamed political operative that the FBI claims helped her to make contacts with influential Republicans.