Claims of national joint-stock company Naftogaz Ukrainy on the assets of state-run enterprise Chornomornaftogaz in Crimea seized by Russia could be settled only at court, Energy and Coal Industry Minister of Ukraine Volodymyr Demchyshyn has said.

"I don’t see other decision, but [settling the dispute] at court," he told reporters after a cabinet meeting on Thursday.

The minister said that he did not see the sum in Naftogaz Ukrainy's claim against Russia on Chornomornaftogaz, but he is convinced that these are dozens of billions of U.S. dollars.

He said that before Russia annexed Crimea, Chornomornaftogaz produced 2.5 billion cubic meters of gas a year and 2 billion cubic meters were stored in underground storage facilities. Chornomornaftogaz had billions of U.S. dollars on its balance sheet.

As reported, Naftogaz Ukrainy has sent the official letter informing on the investment dispute under the bilateral agreement on mutual protection of investment to the Russian Federation.