The Ukrainian government filed a case in an international court of arbitration challenging the gas bills sent by Russian energy company Gazprom. In April, Gazprom sent Ukraine an $11 billion bill for not taking enough gas in 2013 under a take-or-pay contract.
"Right now, we cannot even accept any suggestions regarding preferential terms, given that Ukraine has appealed to the arbitration court," he said.
Gazprom suspended gas deliveries to Ukraine because of the debt issue. With Ukraine hosting the bulk of the Russian gas transits to Europe, the Kremlin has warned European leaders the region's energy security is at risk because of Ukraine's debts.
Poroshenko offered no direct comment on the gas issue other than to say trilateral talks with his European and Russian counterparts was scheduled Sept. 6.