MOSCOW, May 7 - Ukraine and countries in Europe are ramping up imports of Russian gas in anticipation of a new transit crisis that could come in early June, data from Central Dispatching Department of the Fuel and Energy Complex (CDU TEK) indicates.

Unless Naftogaz Ukrayiny pays $1.2 billion on Wednesday, May 7, for the Russian gas it received in April, Gazprom may begin requiring prepayment for the gas it delivers to Ukraine, a move that could trigger a reduction or complete shutoff in transit of Russian gas to Europe.