NEW : Ukrainian Vice President Biden to attend inauguration for new Ukrainian president . Donetsk , Ukraine ( CNN ) -- Five militants were killed in the volatile eastern Ukrainian city of Luhansk on Monday after they took part in a large coordinated assault on a border guard base , an official at the Ukrainian State Border Guard Service told CNN . NEW : Five people die in explosion in government building in same city . Seven militants have been killed , CNN says . The militants are shooting from nearby residential buildings , the official says .
NEW : Ukrainian Vice President Biden to attend inauguration for new Ukrainian president . NEW : Five people die in explosion in government building in same city . Seven militants have been killed , CNN says . The militants are shooting from nearby residential buildings , the official says .