Two police officers were killed and three injured when their convoy came under attack in Russia's North Caucasus Republic of Dagestan, the region's interior ministry said on Tuesday, RIA Novosti reported.
A spokesman said the attackers, hiding in a nearby forest, blew up an explosive device and fired shots as the convoy was returning from a special operation in the republic.
"Law enforcers returned fire. When the scene was examined in daylight, traces of blood were found nearby, so some of the attackers were possibly wounded or killed," he added.
Russia has been fighting terrorists in its volatile southern republics for over a decade. Terrorist attacks are common in the mainly-Muslim region and regularly stray to the Russian capital.