Suicide bombers killed at least 12 people in Russia's North Caucasus 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 Dagestan bombings came 48 hours after Moscow was hit by twin blasts that killed 39. Authorities blamed female suicide bombers with connections to the mainly Muslim North Caucasus. However, the militant separatist group led by a prominent Chechen rebel denied responsibility for the metro bombings in Moscow. “We did not carry out the attack in Moscow, and we don't know who did it,” Shemsettin Batukaev, a spokesman for the Caucasus Emirate organization, told Reuters by telephone in Turkey. 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 200 kilograms of 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's police chief Vitaly Vedernikov and several other officers, authorities said. The two explosions killed 12 people, including nine police officers and a prosecutorial investigator, and 23 others were hospitalized, the federal Investigative Committee said.