"That poor girl is in custody [in the US], she is facing 15 years in prison, but for what? When I heard that something was happening around her… I immediately asked all the chiefs of our intelligence services who she was? No one knows anything about her at all, except some people in the Federation Council, where it seems she has worked for one of the lawmakers, that's all," Putin said during his meeting with members of Russia's Human Rights Council.

READ MORE: US Judge Appoints Advisory Counsel to Represent Maria Butina — Court Filing

Butina, 30, was detained in the United States in mid-July. She was residing in the country on a student visa while completing masters degree in international relations at American University in Washington, DC. Moscow has criticized the US government for Butina's arrest, insisting that the charges against her are groundless.

Butina previously pleaded "not guilty" to charges of acting as a foreign agent and conspiracy to act as an agent of the Russian Federation in the United States. She could face up to 15 years in prison on both charges. However, ABC news reported on Monday, citing court filings, that Butina had agreed to plead guilty to conspiracy charges and will cooperate with US authorities as part of a deal made with prosecutors.