A US federal judge has sentenced Siberian native Maria Butina to 18 months in prison for conspiring with a Russian official to infiltrate a gun rights group and influence American conservative activists and Republicans.

US District Court Judge Tanya Chutkan imposed a sentence that matched the prison term prosecutors had requested.

She also agreed to have Butina, 30, deported back to Russia after she completes the sentence, which will include the approximately nine months she has already served in jail since her July arrest.

Lawyers for Butina, a former graduate student at American University in Washington who publicly advocated for gun rights, had asked the judge to impose a sentence of time served.

Clad in a green prison jumpsuit, Butina begged the judge for leniency and said she was “deeply sorry”.

An undated handout photo of Russian national Maria Butina.

“For all the international scandal my arrest has caused, I feel ashamed and embarrassed. My parents taught me the virtue of higher education, how to live life lawfully, and how to be good and kind to others,” Butina said.

“I have three degrees but now I’m a convicted felon with no job, no money and no freedom,” Butina added, referring to her academic degrees.

“This was no simple misunderstanding by an over-eager foreign student,” Judge Chutkan said before imposing the sentence on Friday.

Butina admitted to conspiring with a Russian official and two Americans from 2015 until her July arrest to infiltrate the National Rifle Association, a group closely aligned with US conservatives and Republican politicians including President Donald Trump, and create unofficial lines of communication to try to make Washington’s policy towards Moscow more friendly.

In fact, Mr Trump addressed an NRA conference about an hour after Butina was sentenced.

Alexander Torshin, who was a deputy governor of Russia’s central bank, has been identified as the Russian official.

Mr Torshin was not charged, but he was hit with sanctions by the US Treasury Department in April 2018.

One of the two Americans referenced by prosecutors was Butina’s then-boyfriend Paul Erickson, a conservative political activist who has not been charged in this case, but faces criminal charges of wire fraud and money laundering in a separate case in South Dakota.

Prosecutors have said that while Butina did not engage in “traditional” spy craft, she worked behind the scenes in conservative political circles to establish ties and boost the US-Russia relationship.

That included actions such as arranging dinners in Washington and New York and attending events to meet high-profile politicians.

Many of those meetings have been documented on Butina’s social media pages.

Her lawyers have said these activities were not conducted with any malfeasance, and downplayed the crime as a simple failure to notify the Justice Department of her activities on Russia’s behalf.

“If I had known to register as a foreign agent, I would have done so without delay,” Butina said on Friday.

“I just didn’t register because I didn’t know to.”

Prosecutor Erik Kenerson, in his remarks in court, said her activities were more serious than that.

“This is not a registration offence,” Kenerson said.

“This is a case where the defendant acted in the United States as an agent of the Russian government.”

The case against Butina was separate from Special Counsel Robert Mueller’s 22-month investigation of Russian interference in the 2016 US election, which detailed a series of contacts between Mr Trump’s campaign and Russian officials.

-DPA