Near Kaluga, an eight-year-old boy died, two other children and an adult were injured in an accident involving a Kamaz and two foreign cars.
The car collided with a truck and then overturned on another vehicle, the Interior Ministry reported.
The accident occurred at the 404th kilometer of the A-108 highway "The Big Ring of Moscow" in Borovsky District.
Employees of the state's investigation and traffic control team are working at the scene of the incident.