An Amnesty International researcher has said he was abducted, stripped, beaten and mock-executed by masked men who said they were police while observing protests in the Russian region of Ingushetia.

Oleg Kozlovsky, 34, who suffered a fractured rib in the ordeal, filed a complaint to Russia's investigative committee last Tuesday. He has fled the country with his family.

“I've been engaged in social work for more than 18 years and lots of various strange, unpleasant and absurd things have happened to me,” Mr Kozlovsky wrote in a Facebook post on Monday. “I've been conscripted into the army from the street, my door has been broken down, I've been detained as a suspect in a double murder, I've been chased in a car and so on and so forth. But what happened a week ago in Ingushetia was so wild it exceeds everything else.”

Mr Kozlovsky went to Ingushetia, a tiny mountainous region on the border with Georgia, on October 5 to monitor ongoing protests over its controversial territory swap with the neighbouring Chechnya region.

The next evening, an unknown man lured the activist out of his hotel in the regional capital Magas on the pretext that one of the protest leaders wanted to meet with him.