MOSCOW -- A prominent human-rights activist was kidnapped and killed Wednesday in Russia's troubled Caucasus area, the latest incident in a spiral of violence in a region that the Kremlin had recently declared pacified.

Rights advocates blamed the pro-Kremlin strongman in the region, Chechen President Ramzan Kadyrov, for the killing of Natalya Estemirova. Mr. Kadyrov, who swears loyalty to the Kremlin and calls Prime Minister Vladimir Putin a hero, has seen his own authority in Russia boosted in recent months, as the Kremlin declared an end to the war in Chechnya and turned over most antiterrorist operations to his troops.

A number of Mr. Kadyrov's critics have been killed recently outside Russia in places such as Dubai, Istanbul and Vienna, crippling his political opposition. Mr. Kadyrov, 32 years old, denies involvement in those killings and scoffs at allegations by human-rights groups that he and his forces torture, kidnap and kill opponents within Russia.

Mr. Kadyrov couldn't be reached to comment Wednesday.

Ms. Estemirova worked for Russian human-rights group Memorial, gathering evidence of abuse by authorities in Chechnya since the beginning of the second war there in 1999. Witnesses said she was forced into a car in Grozny, the Chechen capital, as she headed to work Wednesday morning. Her body was found hours later by a roadside in the neighboring province of Ingushetia. Ms. Estemirova had been shot twice in the head at close range.