A bomb exploded Friday outside a government office in the southern Russian city of Makhachkala, killing a top-ranking police official, the regional Interior Ministry said.

The bomb was planted on the roadside in the center of Makhachkala, the capital of the restive Dagestan region.

The blast killed the deputy head of the ministry's criminal investigation department, Magomed Magomedov, who was sitting in a car parked next to the regional office of the Emergency Situations Ministry, said Interior Ministry spokeswoman Marina Rasulova.

Magomedov's driver was wounded, she said.

Dagestan has seen attacks on dozens of police and government officials in recent years, as unrest increasingly spills over from Chechnya, where Russian troops have been battling separatist rebels for more than a decade.