On Saturday evening, unidentified gunmen opened fire with grenade launchers and automatic weapons on a Ural truck carrying the Defense Ministry's troops on the administrative border between the Vedeno and Shali districts in southeastern Chechnya, the source said.
Measures are under way to find the attackers, the source said.
In a separate instance, the police found a cache full of explosives near the village of Duba-Yurt in the Shali district. The police destroyed the cache on the spot, the source said.
Although Moscow has announced the end of the federal anti-terrorism campaign in its troubled North Caucasus republic, occasional fighting still occurs there, sometimes spilling over into neighboring southern Russian regions in the form of attacks on police precincts and officials.
