KYIV, Dec 22 - President Petro Poroshenko has congratulated Ukrainians on Naftogaz Ukrayiny's victory over Gazprom in the Arbitration Institute of the Stockholm Chamber of Commerce, presidential press secretary Svyatoslav Tsegolko has said.

"Today, a significant contribution has been made to the energy security of our state," Tsegolko wrote on his Facebook page on Friday, quoting Poroshenko as saying.