Polls on the annexation were due to conclude in Ukraine’s Kremlin-controlled regions on Tuesday as officials in Moscow carried out repeated warnings of Russia’s use of nuclear weapons to defend the areas against Ukrainian counterattacks.

Kyiv and its allies have denounced the votes as a sham and said the West will never honor the results of the elections, which dramatically upped the stakes in Russia’s seven-month invasion.

Kremlin-appointed officials in the four regions said the result could be announced as early as Tuesday evening or Wednesday.

“The rescue of the people in the areas where this referendum is being held … is the focus of attention of our entire society and the entire country,” Vladimir Putin said during a televised meeting with officials.

His spokesman Dmitry Peskov said the votes would have “radical” legal implications and that the so-called referendums “will also have security implications,” again referring to Moscow’s threats to use nuclear weapons to defend its territory.

Russian forces in Ukraine have suffered severe setbacks this month, both in the east and south of the country, which observers say has pushed Putin to speed up a vote to consolidate Moscow’s authority there.

Putin said Russia will use all available means to defend its territory, implying that after annexing the four regions, Moscow could use strategic nuclear weapons to repel Ukrainian attempts to retake the territory.

“Let me remind you – the deaf who only hear themselves: Russia has the right to use nuclear weapons if necessary,” former leader Dmitry Medvedev warned on social media on Tuesday.

Ukraine’s four Russian-held regions — Donetsk and Lugansk in the east, and Kherson and Zaporizhia in the south — announced the holding of elections just days before voting began last Friday.

Together they form a land connection between Russia and the Crimean Peninsula, which was annexed by Moscow in 2014 and is otherwise only connected to the mainland by a bridge, which is crucial for the Kremlin.

EU spokesman Peter Stano announced the bloc would impose sanctions on organizers of the “illegal” vote after Britain took a similar step earlier in the week.

Meanwhile, French Foreign Minister Catherine Colonna was in Kyiv on a surprise visit to meet with President Volodymyr Zelenskyy and underscored her country’s support for Ukraine’s “sovereignty and territorial integrity”.

Even Moscow’s closest ally since the invasion began, Beijing, after announcing the votes last week, said Russia should respect territorial integrity in the war.

The so-called referendums follow a pattern used by Moscow in Crimea after nationwide street demonstrations toppled Ukraine’s pro-Kremlin president.

As then, the outcome of the election is viewed by observers as a foregone conclusion. Election officials, in many cases escorted by Russian forces, carried the ballot boxes from door to door.

Lawmakers are expected to vote hastily to annex the territories once the results are announced, and Russian news outlets said Putin could sign a law formalizing the land grabs this week.

Ukrainian forces, meanwhile, have continued their counter-offensive in the east, and the governor of the eastern Kharkiv region announced on Tuesday that his forces had recaptured Kupiansk-Vuzlovyi “one of the largest logistics and rail hubs” in the region, without being included in this week’s vote to be privy to.

As fighting continued along the extensive frontline, AFP journalists were led to the country’s last suspected mass grave site at a shell-damaged and abandoned industrial chicken farm.

“I was told by the soldiers who came to our village that they saw a gravesite of soldiers, but they didn’t give the number,” said Lyudmyla Vakulenko, head of the Kozacha Lopan local administration.

The village is located in the eastern Kharkiv region, where dozens of towns and villages were recaptured during a counter-offensive by Ukrainian troops.

Along with the threat to use nuclear weapons, Putin announced the mobilization of hundreds of thousands of Russian men to reinforce the Moscow army in Ukraine, prompting demonstrations and an exodus of men abroad.

The United Nations sounded the alarm on Tuesday after credible reports of nearly 2,400 arrests in less than a week amid nationwide protests in dozens of cities against the draft regulations.

Former Soviet Georgia, which was occupied by Russia in 2008, said the number of Russians crossing its borders has risen to about 10,000 a day since Putin’s announcement.

Kazakhstan, the Central Asian country on Russia’s southern border, meanwhile, said nearly 100,000 people had entered the country since September 21, and its leader Kassym-Jomart Tokayev said the authorities were “ensuring their safety”.