MOSCOW, July 18 (RIA Novosti) - Russian human rights group Memorial, whose activist was killed in Chechnya this week, said on Saturday it had suspended its activities in the North Caucasus republic.

"We cannot take the risk anymore because our work [in Chechnya] has become life-threatening," Alexander Cherkasov, member of the group's executive committee, said in an interview on Ekho Moskvy radio station.

He said the activities of Memorial's center in Chechnya had been suspended also to allow for a period of mourning for the murdered activist.

Human rights activist Natalya Estemirova, who had been investigating kidnappings and disappearances in Chechnya for Memorial, was abducted on Wednesday in the Chechen capital, Grozny, and was later found dead in the neighboring republic of Ingushetia.

Estemirova had earlier worked with journalist Anna Politkovskaya, who was shot dead in Moscow in October 2006, and human rights lawyer Stanislav Markelov, who was killed in the Russian capital in January of this year. Both Politkovskaya and Markelov had been involved in investigations into human rights abuses in Chechnya.

Russia's North Caucasus has seen an upsurge in violence in recent months, despite the Kremlin's decision to end its 10-year counter terrorism operation in Chechnya.