Russian investigators say two traffic policemen have been killed after their vehicle came under fire in Russia's volatile North Caucasus region.

Unidentified attackers "fired multiple shots from an automatic weapon" at two traffic policemen riding in their patrol vehicle in the town of Malgobek in Ingushetia in the early hours of April 8, a local branch of Russia's Investigative Committee said in a statement.

One of the policemen was killed at the scene, while the second officer died in hospital from his injuries, police said.

Violence is common in the North Caucasus region, where Islamic militants have mounted frequent attacks on police and officials, and some have sworn allegiance to the Islamic State extremist group.

Based on reporting by TASS and AFP