Ukraine's foreign ministry condemned "sham elections" being staged by Russia in occupied Ukrainian territories on Friday, saying they were "worthless" and would have no legal standing.
Russia is holding regional elections, including in four Ukrainian regions that it does not fully control - Donetsk, Luhansk, Zaporizhzhia and Kherson.
The ministry said in a statement that the elections taking place on Ukrainian territory "grossly violate the sovereignty and territorial integrity of Ukraine" as well as international law.
"Russia's sham elections in the temporarily occupied territories are null and void. They will not have any legal consequences and will not lead to a change in the status of the Ukrainian territories captured by the Russian army," it said.
Kyiv called on its international partners to denounce the votes and not to recognise the results.
US Secretary of State Antony Blinken on Thursday also described the voting in Russian-occupied areas of Ukraine as "sham elections" and said they were "illegitimate".
The Russian embassy in the US responded by saying on Friday that Washington was meddling in Russia's internal affairs.