An ally of President Vladimir Putin and Russia's top lawmaker on Tuesday backed plans by Moscow-backed separatists in Ukraine to hold referendums paving the way for the annexation of swathes of additional territory in its former Soviet neighbour.
After nearly seven months of war, including a critical battlefield defeat in northeastern Ukraine, Putin is pondering his next steps in a conflict that has triggered the biggest confrontation with the West since the 1962 Cuban Missile Crisis.
Russian-backed officials across 15 per cent of Ukrainian territory - an area about the size of Hungary or Portugal - lined up to request referendums on joining Russia, reports Reuters.
The self-styled Donetsk (DPR) and the Luhansk People's Republics (LPR), which Putin recognised as independent just before the invasion, and the Kherson and Zaporizhzhia regions have asked for votes over less than 24 hours.
Dmitry Medvedev, who served as Russian president from 2008 to 2012 and is now deputy chairman of the Russian Security Council, backed the referendums, which he said 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," 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 the folding in of parts of Ukraine that voted to join Russia.
If Moscow formally annexed a vast additional chunk of Ukraine, Putin would be essentially daring the United States and its European allies to risk a direct military confrontation with Russia, the world's biggest nuclear power.
US President Joe Biden warned in March that a direct confrontation between the NATO military alliance and Russia would mean World War III. Biden and NATO leaders have been careful to say that they do not want NATO troops in direct conflict with Russian troops.
Putin and senior Russian generals and officials, though, already cast the conflict as a broader contest with the West which they say has sent Ukraine advanced weaponry and helps guide Ukrainian forces with intelligence and training that ultimately kills Russian troops.
Putin on Friday brushed off the lightning Ukrainian counteroffensive in recent weeks and cast the conflict as an attempt to prevent what he said was a Western plot to carved up and destroy Russia.
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.
Ukraine says it will not rest until every Russian soldier is ejected from its territory. Kyiv says it will never accept Russian control over its territory and has called on the West to supply more and better arms to fight Russian forces.
It is unclear how the separatists referendums would work in a war. Russian and Russian-backed forces control only around 60 per cent of Donetsk region while Ukrainian forces are trying to retake Luhansk.
Russian forces took the entire Luhansk region earlier in the war, though Ukrainian officials said on Monday they had retaken a village in the region as part of their ongoing counteroffensive.
Ukraine also still holds territory in both Kherson and Zaporizhzhia regions.
"Referendums in the Donbas are essential, not only for the systematic protection of residents of the LPR, DPR and other liberated territories, but also for the restoration of historic justice," Medvedev said.