Ukraine 's Security Service raids country 's state-run gas company . The Russian government says the move is a response to Ukraine's refusal to pay for its debt, which it claims amounts to billions of dollars in unpaid bills and interest payments on loans from Russia. Raid was to search for documents related to gas deal with Russia . Security Service investigating alleged theft of gas by Naftogaz officers .
Ukraine 's Security Service raids country 's state-run gas company . Naftogaz : Raid was to search for documents related to gas deal with Russia . Security Service investigating alleged theft of gas by Naftogaz officers .