Interior minister says militants have attacked police HQ , causing police casualties . Putin says he tried to persuade Poroshenko to resolve crisis through peaceful means . Comment: Poroshenko declares an end to a unilateral cease-fire with pro-Russian separatists .
Interior minister says militants have attacked police HQ , causing police casualties . Putin says he tried to persuade Poroshenko to resolve crisis through peaceful means . Speaker tells Parliament that Ukraine military has restarted operation against militants . Poroshenko declares an end to a unilateral cease-fire with pro-Russian separatists .