MOSCOW - A powerful car bomb killed one policeman and injured four others at a checkpoint between two North Caucasus republics in Russia, the local Interior Ministry said Tuesday.

The terror attack happened at about 4:20 am Moscow time (0020 GMT) on the administrative border between Ingushetia and North Ossetia, yielding up to 30 kg of TNT, and destroyed everything in 80-meter radius, police said.

"When the policemen at the checkpoint approached the Ingushetia-registered car, the suicide bomber detonated an explosive," a police spokesperson told reporters.

After the explosion, head of North Ossetia, Taimuraz Mamsurov, vowed that terrorists would fail to destabilize the region.

Violence is common in the troubled Northern Caucasus republics in Russia where attacks against police stations and government institutions occur nearly daily since the mid-1990s.