People living in Russian-occupied areas of Ukraine are being asked to vote in what the authorities are describing as local elections.
Ukraine's foreign minister called the polls a "sham", saying the votes would not have any legal standing. Candidates are all either Russian or pro-Russian, and include governors hand-picked by Moscow.
Many taking part in early polling have been asked to cast their votes in the presence of armed Russian soldiers.
Ukrainian officials have warned people not to participate. They say any Ukrainian citizens involved in organising the elections can expect to be punished in the future.
The Council of Europe, a human rights body, condemned the move in the "illegally annexed Ukrainian territories" as a "flagrant violation of international law, which Russia continues to disregard".
Not only are these areas an integral part of Ukraine, but the decision to hold elections there "creates the illusion of democracy", the council said in a statement.
US Secretary of State Antony Blinken also decried the polls saying: "Russia's sham elections in occupied areas of Ukraine are illegitimate." This sparked a response from the Russian embassy in the US, which accused Washington of meddling in Moscow's internal affairs.
Russia's formidable first line of defences in that region, suggesting the counter-offensive there is poised to gain momentum.
Analysts at the US-based Institute for the Study of War (ISW) say recent advances there are "tactically significant" and are "widening the Ukrainian breach of Russian defensive lines in the area and threatening Russian secondary lines of defence".
The focus of Ukraine's efforts there have been around the village of Robotyne, which is some 56km (35 miles) south-east of the city of Zaporizhzhia, the regional capital. Kyiv would like to see its forces cut the Russian supply lines that allow Moscow's forces to maintain a presence in the southern part of the Kherson region, reports UNB.