MOSCOW (AFP) - Russia's Gazprom has pushed back its ultimatum to Ukraine on imposing pre-payment for gas to June 9 after receiving part-payment of US$786 million (S$987 million), Gazprom chief executive Alexei Miller said on Monday.

"Ukraine has paid the first installment for gas supplies. Today US$786 million entered Gazprom's account," Miller was quoted as saying in a company statement. "We welcome Ukraine starting to pay back its debt and postpone the pre-payment regime until June 9."