Russia is said to have ordered Ukraine to pay for gas in advance for all future deliveries starting from June.

It made the demand after Ukraine failed to pay the bill for previous natural gas imports, the deadline for which is believed to have expired on Wednesday. Last month Russian energy giant Gazprom bumped up the amount Ukraine pays for gas by a third.

Russian Energy Minister Alexander Novak said Ukraine will receive only the volume of gas it has paid for by the end of May.

He has been quoted as saying: “According to contract… failure of obligations automatically leads to a switch to prepayment for gas deliveries for Ukraine starting from June 1.

“Russia can’t and should no long carry the burden of support of Ukraine’s economy alone, giving it discounts on the gas price and forgiving debts, in fact covering the deficit in Ukraine’s trade.”

Russia had threatened to cut gas supplies to Ukraine next month if it receives no payment by the end of May. Estimates suggest the nation imports roughly half of the gas it consumes every year from Russia.