MOSCOW (AFP) - A journalist in Russia's restive Dagestan region was killed in a shooting on Tuesday that investigators have linked to his professional work.

Akhmednabi Akhmednabiyev, a journalist with Novoye Delo newspaper based in Makhachkala was struck by "many shots" fired by an unidentified gunman early Tuesday and died on the spot in the outskirts of Makhachkala, Russia's Investigative Committee said in a statement.

"The investigation's top theory is that that Akmednabiyev's murder is related to his professional work," the statement said.

Akhmednabiyev, who was the deputy editor of his newspaper, covered political issues, according to the weekly's website, with recent articles focusing on the reasons behind near daily attacks in the region.

Investigators said he was attacked in January, when gunmen opened fire on his car, but he was not injured.

Attacks on journalists are frequent in Dagestan, Russia's most violent region because of a simmering Islamist insurgency. A young news anchor was shot dead in Makhachkala in December 2012, and the editor of a prominent opposition newspaper, Khadzhimurad Kamalov, was shot dead in 2011.

That crime remains unsolved despite calls by the UN human rights agency and media watchdog groups to push ahead with the investigation.