Ukrainian state-owned energy firm Naftogaz said on Wednesday Russia’s Gazprom would have to pay it $2.56 billion after a Stockholm court found in Naftogaz’s favor in the final stage of a long-running legal battle. In June 2014, Gazprom and Naftogaz lodged multi-billion-dollar claims against each other with the Stockholm arbitration court, which resolves commercial disputes. The disagreement was a by-product of the worsening relations between Kiev and Moscow since Russia’s annexation of Crimea and the eruption of Russian-backed separatist violence in Ukraine’s Donbass region, which has killed more than 10,000 people.