UN Secretary General Ban Ki-moon on Wednesday deplored plans by Ukrainian separatist rebels to hold elections at the weekend, saying the polls undermined peace accords.

The vote on Sunday in east Ukraine "will seriously undermine the Minsk Protocol and Memorandum, which need to be urgently implemented in full," Ban said in a statement released by his spokesman.

Ban's criticism came after Russia raised tensions by saying that it would recognize the result of the vote in the Donetsk and Lugansk regions.

The UN chief said he "deplores the planned holding by armed rebel groups in eastern Ukraine of their own 'elections' on 2 November, in breach of the constitution and national law."

Pro-Russian rebels in Ukraine's self-proclaimed Donetsk and Lugansk People's Republics announced last month plans to hold polls on Sunday to elect regional leaders and legislative bodies.

Ukraine's national parliament in Kiev, the Verkhovna Rada, has passed legislation giving the rebel-held, mainly Russian-speaking regions limited self-rule.

The legislation called for local elections to be held on December 7. But the rebel leaders said they should have powers to set the date.

The United States has said that recognizing the rebel vote would be a "clear violation" of the Minsk accords signed in the Belarussian capital on September 5.

Ukraine and the West accuse Russia of backing the separatist rebels fighting Kiev, but Russia denies any involvement. More than 3,700 people have died in the conflict since April.