Kiev has asked Moscow to compensate it for the damage caused by the loss of offshore energy reserves in Crimea, following the peninsula's incorporation into Russia. "On April 28, Ukraine's Naftogaz sent a letter to Russia's Gazprom offering to settle the issue at the corporate level," Igor Didenko, Ukrainian Deputy Energy and Coal Industry Minister, told a press conference Thursday. Didenko said Kiev asked Moscow to pump 2 billion cubic meters of natural gas into Ukraine's underground storage reservoirs as compensation for the loss of Chornomornaftogaz, a company which pumps oil and gas from the Black Sea shelf. On Wednesday, Justice Minister Pavlo Petrenko said Kiev estimated losses from the Crimean crisis and the nationalization of Ukraine's property in the peninsula at 85 billion U.S. dollars and warned that Ukraine would seek financial compensation from Russia for "seized assets". On March 18, Russian President Vladimir Putin signed a treaty to integrate Crimea and its city of Sevastopol into Russia, following a referendum among Crimeans strongly supported the move.