The attack occurred in the outskirts of the city of Buynaksk, to the southwest of the republic's capital of Makhachkala, on Wednesday night when five police officers were on duty, a spokesman said.
The platoon commander died at the scene from his wounds. A criminal case has been opened into the attack.
In the neighboring republic of Chechnya on Wednesday, a Russian officer was killed in an explosion in the central Urus-Martan district, a local police spokesman said.
The blast occurred as troops conducted a search of a forest. The explosive device contained the equivalent of 1 kilogram of TNT.
Sporadic terrorist attacks and militant clashes remain common in Russia's North Caucasus, particularly in the republics of Chechnya, the site of two brutal separatist wars in the 1990s and early 2000s, and Ingushetia, which has seen a marked increase in fighting between federal forces and militants.