Prominent human rights group Memorial says masked attackers have torched its office in the region of Ingushetia in Russia's North Caucasus.

The arson attack that Memorial said happened in the early hours on Wednesday came a week after the chief of the group's branch in neighboring Chechnya was detained on suspicion of drug possession. The man's arrest has been widely regarded as a payoff by Chechen authorities for Memorial's work exposing rampant rights abuses in the North Caucasus.

Memorial said in a statement on Wednesday they believe the attack is linked to the crackdown on Memorial in Chechnya.

Repression against government critics and rights advocates has often spilled over from Chechnya to neighboring Ingushetia, where Chechen operatives have been known to have a free hand.