A truck carrying Russian Interior Ministry troops came under fire in the region of Dagestan. At least one soldier reported dead.
The attack occurred around 2200GMT in the western city of Khasavyurt, near the border with Chechnya, said Abdul Musayev, of the Dagestani regional Interior Ministry. Police were still looking for the attackers.
The shooting was the latest in a long line of attacks on police and government officials in the Caspian Sea province.
40 law enforcement officers had been killed in terrorist attacks in Dagestan since the beginning of the year, along with an unknown number of killed and wounded military soldiers and civilians, the AP quoted regional leader Magomedali Magomedov as saying.
NATO's Boeing P-8 Poseidon was circling above the easternmost point of Romania at the time of the missile strike on the Black Sea Fleet headquarters in Sevastopol