"One more Russian was arrested in the US without any plausible reason. We demand her immediate release. Let’s support her with a tag #FreeMariaButina," Polyanskiy said on Twitter.
Butina, 29, is a student from Russia who has recently graduated from American University in Washington DC with a Master’s Degree in International Relations. Last Sunday, the US authorities arrested her and charged with conspiracy to act and acting as a foreign agent.
On Wednesday, she denied both charges in federal court in Washington but was remanded in custody without bail, as she is considered a flight risk. She faces up to 15 years in jail.
Russian Foreign Ministry spokeswoman Maria Zaharova said Butina was detained right before the summit between US President Donald Trump and Russian President Vladimir Putin in Helsinki in an effort to minimize the positive outcomes of the meeting.