Suicide bomber kills 4 officers at police post in southwest Russia March 6, 2012 -- Updated 2156 GMT (0556 HKT) The attack occurred in a town near the Caspian Sea coast; 2 others were injured Dagestan has been the scene of attacks by Islamist rebels for years Three police officers were killed in an attack on a polling station Sunday (CNN) -- A woman blew herself up at a police post in Russia's southwestern republic of Dagestan, killing four officers and wounding two more, the state-run news agency RIA Novosti reported Tuesday. The attack occurred in the village of Karabudahkent, near the Caspian Sea coast, according to RIA Novosti. It was not clear whether the woman was approaching the officers on foot or in a car, the agency quoted a regional government spokesman as saying. Violence has plagued Dagestan for years as Islamist rebels fight Russian rule over the northern Caucasus region. Tuesday's bombing follows an attack on a polling station that killed three police officers during Russia's presidential elections Sunday, a police spokesman said. CNN's Igor Krotov contributed to this report.