MOSCOW, June 2 (RIA Novosti) - There is no possibility of cutoffs of natural gas supplies to Ukraine now that a 10-year supply contract has been signed, Gazprom's chief executive said on Tuesday.

Alexei Miller said even if 100% prepayment for gas deliveries was introduced, it would be up to Ukraine to decide how much gas to buy.

"They will get as much as they pay for. There's no question of cutoffs," he said after a meeting with Oleh Dubyna, head of Ukrainian energy company Naftogaz, in Moscow.

Miller said it was still "unclear" whether Naftogaz would be able to pay its bills for May supplies.

"As you know, payment must be made before June 7," he said.

Russia's prime minister said in late May it was unlikely that Moscow would be able to grant Ukraine $5 billion in advance payments for natural gas transits over 5-7 years and warned of rising risks of Russian gas transit disruptions.

Vladimir Putin also said in a statement on his website that the European Union appears unable to help Ukraine finance gas shipments. Ukraine transits around 80% of Russia's Europe-bound gas.

Kiev earlier said it may be unable to pay Russia for current shipments, raising concerns about a fresh dispute that may affect EU consumers.

A bitter price and debt rows between the ex-Soviet republics led to disruption in shipments to Europe at the turn of the year.

Energy spats between Russia and its ex-Soviet transit nations have triggered concerns in Europe about too much reliance on Russian shipments, prompting it to seek alternative suppliers. Moscow has also been accused of using energy as a political tool.