It would be premature to claim that Ukraine and Russia have reached an agreement on gas, said Ukrainian Prime Minister Arseniy Yatseniuk.

"It would be premature to be saying that we have reached any agreement. Agreements have relevance when they are signed – by Gazprom and Naftogaz – and when gas starts flowing. Now it's mere talk. There are no reasons for me to trust Putin," he said on ICTV television on Sunday evening.

Yatseniuk also said that Ukrainian underground gas storage facilities contain 16.7 billion cubic meters of gas and that Ukraine needs 5 billion cubic meters more as a minimum to go through the winter comfortably.

He noted at the same time that Ukraine has ample resources to provide heating to Ukrainian homes.

Reverse gas shipments to Ukraine from Europe will hopefully increase, the prime minister said.

"We currently get 60% of the reverse gas. Europe could increase the volume of reverse shipments and we would buy all gas in Europe," Yatseniuk said.

But he also said that Ukraine would not be able to deliver gas to Donetsk and Luhansk if it does not get it from Russia.