MOSCOW (AP) — A Russian court has imposed a heavy fine on one of the country's most prominent human rights activists for taking part in a small demonstration in Red Square.

Svetlana Gannushkina was fined 150,000 rubles ($2,300) on Tuesday, according to the human rights group Memorial.

Gannushkina, a veteran human rights activist and a board member of Memorial, won the Right Livelihood award, often called the alternative Nobel Prize, in 2016.

She was fined for participating this month in a picket on Red Square, marking the 10th anniversary of the abduction and killing of Natalia Estemirova, the director of Memorial's Chechnya office, and complaining that her slaying has not been adequately investigated.

Memorial chairman Alexander Cherkasov was also fined 10,000 rubles ($150) for the demonstration.