Two police officers have died after an attack by unknown militants in the Daghestani town of Khasavyurt.
One of the officers died at the scene, the other in a local hospital.
Officials say the attackers opened fire on the officers' vehicle, then stole a car and drove away.
The stolen car was later found some two kilometers from the scene of the attack.
In nearby Ingushetia, police shot dead two militants late on March 30.
Reports say police attempted to stop a car on the outskirts of the Ingush capital, Nazran, when the car's occupants opened fire. The two were killed when police returned fire.
Russia has waged a long campaign to stabilize the situation in its North Caucasus region but shootings, bombings, and other violence continue to plague the region.
Based on reporting by ITAR-TASS and Interfax