At least five police were killed and another ten wounded in a blast near a traffic police post in the capital of Russia's North Caucasus Republic of Dagestan, RIA-Novosti reported on Wednesday.
The blast occurred at about 7.55 a.m. Moscow time (4:55 GMT) near Makhachkala.
"According to preliminary information, five people were killed and another ten wounded after a suicide bomber drove a vehicle into the gates of the traffic police headquarters," the law-enforcement bodies said.
Russia's mainly Muslim North Caucasus republics, especially Chechnya, Dagestan and Ingushetia, have seen an upsurge of militant violence lately, with frequent attacks on police and officials.
Prime Minister Vladimir Putin has earlier pledged to wage "a ruthless fight" against militant groups but also acknowledged a need to tackle unemployment, organized crime, clan rivalry and corruption as causes of the ongoing violence.