MAKHACHKALA (Russia) (Reuters/AFP) Suicide bombers killed at least 12 people in Russias North Caucasus on Wednesday, two days after deadly attacks in Moscow that authorities linked to insurgents from the region. A car packed with explosives blew up as police gave chase, and a bomber in a police uniform set off a second blast in a crowd of police who rushed to the scene, authorities said. The coordinated attacks in the town of Kizlyar, in Dagestan region close to its border with Chechnya, were the latest outbreaks in a surge of violence in the Caucasus a decade after the Kremlins second of two wars against Chechen separatists. The Dagestan bombings came 48 hours after Moscow was hit by its bloodiest attack in six years - twin morning rush-hour blasts that killed 39. Authorities blamed female suicide bombers with connections to the mainly Muslim North Caucasus. Prime Minister Vladimir Putin said a single group could be behind the bombings in both Moscow and Dagestan. He called the attacks a crime against Russia and ordered Interior Minister Rashid Nurgaliyev to bolster the police presence in the North Caucasus. The attack in Kizlyar began when a car packed with explosives blew up after its driver ignored a command to halt and sped toward the centre of town with police close behind, Nurgaliyev, the Interior Minister, said in televised comments. The vehicle - a black four-wheel-drive Niva - exploded with the force of as much as 200kg TNT, Russian news agencies quoted prosecutorial investigators as saying. Two police officers were killed, Nurgaliyev said. Twenty minutes later, a suicide bomber pushed his way into a crowd of police who had gathered at the site and detonated his explosives, killing Kizlyar police chief Vitaly Vedernikov and several other officers, authorities said. After the blasts, two gutted cars stood near a deep crater on a debris-strewn street lined by bare trees. A red brick schoolhouse had its windows blown out and roof partly ripped off. A mans severed head lay on the street. Reports said there were no children in the school at the time of the blasts. The two explosions killed 12 people, including nine police officers and a prosecutorial investigator, and 23 people were hospitalised, the federal Investigative Committee said. Meanwhile, the leader of the Islamic Emirate of the Caucasus Doku Umarov has claimed responsibility for this weeks Moscow metro bombings, the SITE monitoring group reported on Wednesday. Doku Umarov, the leader of the Islamic Emirate of the Caucasus, claimed responsibility for the 3/29 metro bombings in Moscow in a Russian-language video released on March 31, 2010, SITE Intelligence Group said.