MOSCOW (Reuters) - One of Russia’s biggest human rights groups said on Wednesday that the head of one of its offices in the south of the country had been attacked near his home, an assault that the group, Memorial, said was linked to his work.

Memorial, which has angered authorities in the wider region by exposing rights abuses, believes it is being targeted by a campaign designed to drive it out.

It said Sirajutdin Datsiev, who ran its office in Dagestan, had been struck hard on the back of a head with an unknown object by an attacker shortly after leaving his home in the city of Makhachkala on Wednesday morning.

Datsiev had fallen to the floor, but had been unable to move his head and had therefore not seen his assailant, Memorial said in a statement, citing an unnamed eye witness as saying his attacker had jumped out of a car with tinted windows.

“We consider that the attack on Sirajutdin Datsiev was linked to his professional activity,” Memorial said, saying the police were looking into the incident.

In January, Memorial’s office car in Dagestan was torched and employees received phone threats saying the office there would be set alight with them inside it.

Two masked men set fire to another Memorial office in nearby Ingushetia that same month, while police in Chechnya detained the head of its office there and accused him of possessing a large quantity of cannabis in what he said was a set-up.

Both the United States and the European Union have expressed concern over Memorial’s problems.