MOSCOW (Reuters) -- Gunmen have killed three police officers and a passerby in Daghestan in southern Russia, news agencies said, a region where increased violence could destabilize the whole country.
The attackers fired at a police checkpoint in Daghestan's capital, Makhachkala, at around 8:40 p.m. (1740 GMT) before fleeing. The police officers returned fired and killed one of the attackers, a police source told RIA Novosti news agency.
Over the last two years, violence has spread across the North Caucasus from Chechnya, where Russian forces have fought two wars against rebels since 1994.
Bomb attacks and shootouts occur almost daily in Daghestan, but a death toll of three police officers, one pedestrian, and one of the attackers is higher than usual. In October, five police officers were killed and another nine were wounded in an attack.
A mixture of economic frustration and heavy-handed police tactics make Daghestan a fertile recruitment ground for radical Islamists looking for disenchanted young men, analysts have said.
This week, Russian security forces said that intensifying violence in the region could destabilize the entire country.