Seven militants are killed in Dagestan 's capital , Makhachkala , Russian state media report . Investigators say the counterterror operation followed an attack Friday , state media say . Security has been stepped up in Russia ahead of the Winter Olympics next month . TL;DR A suicide bomber kills at least seven people and wounds dozens more outside a police station in Russia's southern city of Volgograd on Saturday.
Seven militants are killed in Dagestan 's capital , Makhachkala , Russian state media report . Investigators say the counterterror operation followed an attack Friday , state media say . Security has been stepped up in Russia ahead of the Winter Olympics next month . Dagestan is about a 12-hour drive from Sochi , host city for the Games .