Western leaders are lining up to slam Russia’s plans to hold “sham” referendums that would effectively hand parts of Ukraine to Moscow.

Kremlin-backed officials in four areas of Ukraine – about 15 per cent of the country – lined up on Tuesday night to request a vote on whether to join Russia.

Unsurprisingly, Vladimir Putin’s government expressed support for the separatists’ plans.

The move could sharply escalate the conflict and not just because it would stir up anger in Ukraine; annexing parts of Ukraine could allow Russia to claim that weapons supplied by allies were directly threatening its territory.

Ukrainian volunteer soldier and famous ballet dancer Oleksandr Shapoval is among the recent victims in the Donetsk region. He was killed last week. Photo: Getty

The self-styled Donetsk (DPR) and the Luhansk People’s Republics (LPR), which Mr Putin recognised as independent just before the invasion, and the Kherson and Zaporizhzhia regions have asked for votes over less than 24 hours.

Luhansk, Donetsk and Kherson officials said the referendums would take place in just days – on Friday, September 23, to Monday, September 27.

Russia does not fully control any of the four regions, with only about 60 per cent of the Donetsk region in Russian hands.

Asked about the referendums, Russian Foreign Minister Sergei Lavrov said: “From the very start of the operation… we said that the peoples of the respective territories should decide their fate, and the whole current situation confirms that they want to be masters of their fate”.

US Secretary of State Wendy Sherman called the referendum a ‘sham’. Photo: Getty

If Russia formally annexed a vast additional chunk of Ukraine, Mr Putin would essentially be daring the US and its European allies to risk a direct military confrontation with Russia, the world’s biggest nuclear power.

“All this talk about immediate referendums is an absolutely unequivocal ultimatum from Russia to Ukraine and the West,” Tatiana Stanovaya, founder of the political analysis firm R.Politik, said.

Ukrainian and American officials called the referendums a “sham”.

On Wednesday morning, the United Nations General Assembly – meeting in-person for the first time in three years – is hearing from other world leaders who are addressing the conflict.

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Dmitry Medvedev, who was Russian president from 2008 to 2012 and is now deputy chairman of the Russian Security Council, backed the referendums. He said they would change the path of Russian history and allow the Kremlin more options for defence of what he said would become Russian territory.

“Encroachment onto Russian territory is a crime which allows you to use all the forces of self–defence,” Mr Medvedev said in a post on Telegram.

“This is why these referendums are so feared in Kyiv and the West.”

“It is equally important that after the amendments to the constitution of our state, no future leader of Russia, no official will be able to reverse these decisions.”

Vyacheslav Volodin, the Speaker of Russia’s lower house of parliament, the Duma, said he would support folding in parts of Ukraine that voted to join Russia.

Ukraine said the threat of referendums was “naive blackmail” and a sign Russia was running scared.

“This is what the fear of defeat looks like. The enemy is afraid and obfuscates primitively,” said Andriy Yermak, chief of staff to Ukrainian President Volodymyr Zelensky.

“Ukraine will solve the Russian issue. The threat can only be eliminated by force.”

Ukraine said it would never accept Russian control over its territory and called on other countries to supply more and better arms to fight Russian forces.

Russia’s parliament on Tuesday approved a bill to toughen punishments for a host of crimes such as desertion, damage to military property and insubordination if they were committed during military mobilisation or combat situations.

The conflict in eastern Ukraine began in 2014 after a pro-Russian president was toppled in Ukraine’s Maidan Revolution and Russia annexed Crimea, while Russian-backed separatists in the Donbas –which is comprised of Donetsk and Luhansk – sought to break away from Kyiv’s control.

Russian forces took control of Crimea, which has an ethnic Russian majority and was transferred to Ukraine in Soviet times, on February 27, 2014. A referendum on joining Russia was held on March 16 of that year, with Crimean leaders declaring a 97 per cent vote to secede from Ukraine.

Russia formally added Crimea on March 21.

Ukraine said the referendum violated its constitution and international law.

-with AAP