Amid the ongoing tensions , Ukraine 's National Guard base in the eastern Luhansk region was attacked Wednesday by what the country 's Interior Ministry described as `` terrorists . '' Slovyansk official : Tens of thousands of Estonian troops along border have been moving back . Acting president says Russian grenade launcher downed helicopter . Putin governor says he is in talks with separatist leaders , aims to calm situation . Self-declared separatist mayor of Slovyansk says militants hold Tens of thousands missing the Donetsk People 's Republic monitors .
Slovyansk official : Tens of thousands of Estonian troops along border have been moving back . Acting president says Russian grenade launcher downed helicopter . Putin governor says he is in talks with separatist leaders , aims to calm situation . Self-declared separatist mayor of Slovyansk says militants hold Tens of thousands missing the Donetsk People 's Republic monitors .