The respected Russian human rights group Memorial is suspending the work of its office in Chechnya, a member of the organization's executive committee says.
The decision came after the kidnapping and killing of Natalya Estemirova, one of the group's main activists in the region.
"We will suspend work at our offices in Chechnya and will decide on how to operate there in future," Aleksandr Cherkasov, a member of Memorial's Executive Committee, told RFE/RL's Tajik Service in an interview.
"The information we get about human rights violations and crimes committed by local authorities and local law enforcement bodies is disturbing...It is horrifying. But a lack of information from the region would be even more horrifying. We will think about what to do in future."
Russia's Ekho Moskvy radio also quoted Cherkasov as saying that Memorial's office in Chechnya would be temporarily closed.
Memorial spokeswoman Yuliya Klimova told The Associated Press that a closure had been discussed, but she was not aware that a decision had been made.
Memorial's chairman, Oleg Orlov, has accused pro-Kremlin Chechen leader Ramzon Kadyrov of being responsible for the murder of Estemirova, arguing that he was guilty regardless of who ordered the killing. Rights activists also say that by supporting Kadyrov, the Kremlin has created an atmosphere of impunity that encourages abuses.
Kadyrov's lawyer responded to Orlov's allegations by saying he would sue for defamation.
Cherkasov says Memorial is not afraid of a lawsuit.
"Certainly, we are ready to defend ourselves," he said.
Witnesses say Estemirova, who had investigated executions, kidnappings and other abuses, was forced into a car outside her home in Grozny on July 15. She was found shot in the head hours later.
With material from agency reports