Russia's oil price in roubles has fallen to a two-year low below the 4,000 rouble per barrel mark and some 40% lower than planned in the federal budget, data showed, piling pressure on the Kremlin, already saddled with a burgeoning budget deficit.

"I think Russia, with the price of oil right now, oil has gone down, we are in a good position to settle, they want to settle. Ukraine wants to settle," U.S. President Donald Trump said.