The attack took place at 13:15 p.m. Moscow time (9:15 a.m. GMT) on Sunday in the village of Petropavlovskaya. The gunmen opened automatic fire at the Niva car with three security officers, the police source said.
Measures are ongoing to find the attackers, the police source said.
Chechnya saw two Kremlin-led military campaigns in the 1990s-early 2000s against separatist forces. Although the active phase of the operation was completed, frequent militant attacks occur in Chechnya and neighboring republics.