Human rights activists and journalists are leaving Chechnya after a series of murders, saying the danger level in the region has reached the highest level.

The Memorial human rights group has suspended its work in Chechnya, while the opposition newspaper Novaya Gazeta, known for its investigative reports about the region, has withdrawn its reporters.

On Monday, Memorial and Human Rights Watch said they had appealed to federal ombudsman Vladimir Lukin and law enforcement agencies to investigate the latest human rights murders and guarantee their safety in Chechnya.

Memorial said its workers in Chechnya have received death threats and unknown people were following at least three of them in July. Among them were Natalya Estemirova, who was abducted on a Grozny street and killed on July 15, and Akhmed Gisayev, who was investigating an abduction case involving federal forces, Memorial activist Alexander Cherkasov said.

“This is an individual case amid a big campaign,” Cherkasov told The Moscow Times.

Soon after the killing, Memorial shut down its office in Chechnya.

“The level of danger was so high that Memorial had to evacuate its worker [Gisayev],” said Tatyana Lokshina, a researcher with Human Rights Watch.

Last week, two activists with the Chechen-based children’s charity Save the Generation were found dead in the trunk of their car in Chechnya.

The attacks resemble a campaign of intimidation against human rights activities in Chechnya, Lokshina said. “These events are aimed at putting an end to all independent organizations in Chechnya,” she said.

Human rights campaigners had faced pressure before, but now it has reach boiling point, said Nikolai Silayev, a Caucasus analyst with the Moscow State Institute of International Relations. He said previous pressure included attacks on reporters who covered Chechnya such as the 2006 slaying of Novaya Gazeta reporter Anna Politkovskaya.

Politkovskaya, a Kremlin critic who reported about human rights abuses in Chechnya, was shot dead in her apartment building in central Moscow. Her death shocked the world, but Novaya Gazeta and Memorial did not leave Chechnya.

Last week, Novaya Gazeta announced that it was withdrawing all reporters from Chechnya because of a lack of security. Memorial is continuing its work in the region through offices outside Chechnya.

Silayev said Chechnya was becoming more and more closed to the rest of the world and that it was increasingly difficult to understand what was going on there because of a lack of information.

“Chechnya is turning into a closed region like Turkmenistan,” Lokshina said, cautioning that this would hurt the image and security of the entire country.

Ingushetia has seen a series of attacks on government targets, including the suicide bombing of a Nazran police station that killed at least 20 people Monday. But human rights and reporters are staying there.

Chechen President Ramzan Kadyrov said last week that the killings of human rights activists showed that rebels were adopting a new tactic in an attempt to discredit him and other regional leaders.

Human rights groups including Memorial have blamed Kadyrov for the killings, a charge he denies. Kadyrov has filed a defamation lawsuit against Memorial’s chief.