Gunmen opened fire on two policemen in Russia's Ingushetia region.
The shootings occurred after the police stopped a Mercedes in the center of Nazran, Ingushetia's main city, and demanded the four men inside produce identification, the regional Interior Ministry said. Both police officers died at the scene, it said.
Attacks on police and other law enforcement authorities have been common in Ingushetia for several years, but they have spiked sharply in recent months.
Government critics attribute them to anger they say is fueled by abductions, beatings, unlawful arrests and killings of suspects by police and other government forces.
Government authorities usually attribute the violence to local militants or fighters from Chechnya, the site of two separatist wars since 1994.
It is assumed that the fighter will be created using new stealth technologies and have a very large interception range - up to 1,500 kilometers