Russia plans to recognise elections being organised next weekend by rebels in eastern Ukraine in defiance of the government in Kiev.

"We expect the elections will go ahead as agreed, and we will of course recognise the results," said Russian Foreign Minister Sergei Lavrov.

He was speaking to the Izvestia newspaper ahead of Sunday polls staged by two pro-Russian separatist regions to elect leaders and parliaments.

"We are counting on it being a free vote and that it will go ahead unhindered," Mr Lavrov said of the simultaneous polls in the self-proclaimed people's republics of Donetsk and Luhansk.

Mr Lavrov said the elections, which are opposed by the government in Kiev, would be "important from the point of view of legitimising the authority" of the regions' rebel leadership.

The Russian minister also said Russia was likely to recognise parliamentary elections held by Ukraine on Sunday, although it would wait for the verdict of the OSCE observers.

The Ukrainian elections were not held in the rebel-held regions, which are home to three million voters.

"I think Russia recognises the results of the vote," Mr Lavrov said.

"It's very important for us that authorities finally appear in Ukraine who are not engrossed in infighting or pulling the country now to the West, now to the East, but in the real problems that the government faces, as it thinks how to unify the country."

However, a senior Ukrainian foreign ministry official has said the Russian decision to recognise the separatist elections "undermines" attempts to end a six-month conflict there.

"Russia's intentions directly contradict the Minsk (peace) accord, undermine the agreed process on de-escalation and peaceful resolution, and continue to weaken trust in it (Russia) as a reliable international partner," said Dmytro Kuleba.