Three policemen were killed and six others wounded Monday in a pair of attacks in Chechnya and Ingushetia, while another attempted attack on a police station in Ingushetia was foiled, authorities said.
It was not clear if the incidents in the North Caucasus republics were coordinated, but Russian officials said they believed one of the region's armed groups was responsible for all the attacks, which highlight the instability in Russia's south as the country prepares to hold the Winter Olympics in nearby Sochi in February.
President Vladimir Putin has called for increased security in the mainly Muslim North Caucasus, where rebels are waging an insurgency to establish an Islamist state.
The bloodiest attack Monday was in Chechnya, where a suicide car bomber killed three police officers and wounded four others when a vehicle blew up before dawn outside a police station in the village of Sernovodsk, the Interior Ministry said.
News reports cited local officials as saying the car was speeding toward the station and exploded after police raised a barrier.
In Ingushetia, which borders Chechnya on the west, police spotted a car believed to contain insurgents and began chasing it. The occupants of the car opened fire and then blew up the vehicle, wounding two officers, the ministry said.
Earlier Monday, a man bearing an automatic weapon and wearing a belt of explosives approached a police station in the Ingush town of Ordzhonikidzevskaya, but was intercepted by police and persuaded to surrender, the ministry said.
Islamic rebels fought two full-scale wars with Russian troops in Chechnya in the past two decades, but suicide bombings are now uncommon in the republic, which is ruled by Kremlin ally Ramzan Kadyrov.
Ingushetia suffers more frequent attacks attributed to insurgents. The republic of Dagestan, which borders Chechnya on the east, currently experiences the most violence of any region in the North Caucasus.
Material from Reuters and The Moscow Times is included in this report.