WASHINGTON (Reuters) - Maria Butina, who has admitted to working as a Russian agent to infiltrate an influential gun rights group and make inroads with U.S. conservative activists and Republicans, will be sentenced on April 26, U.S. District Judge Tanya Chutkan said on Thursday.

FILE PHOTO: Maria Butina appears in a police booking photograph released by the Alexandria Sheriff's Office in Alexandria, Virginia, U.S. August 18, 2018. Alexandria Sheriff's Office/Handout via REUTERS/File Photo

Butina, a former graduate student at American University who publicly advocated for gun rights, pleaded guilty in December to one count of conspiring to act as a foreign agent for Russia. She has remained in custody since her arrest in July 2018.

The 30-year-old native of Siberia wore a green jail jump suit during the brief hearing in Washington, but said nothing.

Chutkan said during the hearing that sentencing memos from prosecutors and Butina’s defense team will be due a week before the sentencing date. Prosecutors and defense lawyers approached the bench for a discussion with the judge, but the subject of those talks was not made public.

Butina has admitted to conspiring with a Russian official and two Americans from 2015 until her arrest to infiltrate the National Rifle Association and create unofficial lines of communication to try to make Washington’s policy toward Moscow more friendly. The NRA is closely aligned with U.S. conservatives and Republican politicians including President Donald Trump.

Chutkan in February had delayed the sentencing at the request of prosecutors, who said Butina was cooperating in their ongoing investigation. Butina’s attorney, Robert Driscoll, said at the time his client was ready for sentencing.

Russia in December accused the United States of forcing Butina to falsely confess to what it described as the “absolutely ridiculous charges” of her being a Russian agent.

Court records have pointed to the involvement of several others with Butina’s actions including Paul Erickson, a conservative political activist with deep Republican ties who was romantically linked to her. Erickson is referred to as “Person 1” court records, which stated that he helped advise her on which American politicians to target for meetings.

Erickson’s attorney William Hurd declined to comment.

Federal prosecutors in South Dakota have charged Erickson with 11 counts of wire fraud and money laundering unrelated to the case against Butina. Erickson’s indictment appeared to make references to her when it said he made a payment of $8,000 to an “M.B.” in June 2015 and another payment of $1,000 to “M.B.” in March 2017, as well as more than $20,000 to American University in June 2017.

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

The charges against Butina were not part of Special Counsel Robert Mueller’s now-concluded investigation into Russia’s role in the 2016 U.S. election.