Voters in the self-proclaimed "Donetsk People's Republic" and "Lugansk People's Republic" in Eastern Ukraine on Sunday started to elect regional leaders and legislative bodies.
The Ukrainian Foreign Ministry on Tuesday denounced the elections in the two "people's republics" as illegitimate.
UN Secretary-General Ban Ki-moon on Wednesday also deplored the elections, saying the vote will seriously undermine the Minsk Protocol and Memorandum.
These "elections" will seriously undermine the Minsk Protocol and follow-up memorandum, which were signed by the Ukrainian government and opposition groups in the Belarusian capital in September to seek a ceasefire in the east of the country, said Ban.
The Minsk peace accords "need to be urgently implemented in full," he added.
Meanwhile, Russian Foreign Minister Sergei Lavrov on Monday told the Russian "Izvestia" daily newspaper that Moscow will recognize the results of Sunday's polls in Donetsk and Lugansk.
In September, leaders of the self-proclaimed "Donetsk People's Republic" and "Lugansk People's Republic" announced plans to hold elections on Sunday to elect regional leaders and legislative bodies.
Protests demanding independence from the central government in Kiev erupted in eastern Ukraine early April, shortly after Russia absorbed the Ukrainian peninsula of Crimea in March after a referendum.
According to UN, conflicts erupted in eastern Ukraine in mid-April has claimed more than 3,700 lives and injured more than 9,000 others.