Vladimir Putin could use Russia's Victory Day celebrations next month to declare war on "the world's Nazis" and mass mobilise the Russian population, the UK has said.
The 77th Victory Day parade - an annual ceremony to commemorate Russia's efforts in the Second World War - is set to be held on 9 May in Moscow.
However, Western intelligence officials have warned the parade is likely to act as a deadline for Putin to show some results for his war with Ukraine, which has now been raging for over two months.
The Russian president ordered his soldiers to invade Ukraine on 24 February, justifying his actions by claiming he wanted to "de-Nazify" and demilitarise the country - despite President Volodymyr Zelenskyy being Jewish.
But instead of producing an anticipated swift victory, Russia has seen its troops repelled from significant parts of the country as well as galvanising Western allies to stand united in their condemnation of the invasion and impose swingeing sanctions of Moscow.
Kyiv has claimed around 23,000 Russian soldiers have been killed so far. The number has not been independently verified.
On Friday, the UK defence secretary Ben Wallace warned the Russian President could used the Victory Day parade to increase the threat of Nazism.
"I would not be surprised... that he is probably going to declare on May Day that 'we are now at war with the world's Nazis and we need to mass mobilise the Russian people'." he said.
"Putin, having failed in nearly all objectives, may seek to consolidate what he's got... and just be a sort of cancerous growth within the country.
"We have to help Ukrainians effectively get the limpet off the rock and keep the momentum pushing them back."
Although Wallace said there was no intelligence which indicated Putin was planning that announcement, he said his previous speeches gave an indication it was likely.
"We have seen a number of statements from Putin about this becoming a war, 'this is a proxy war' - which it isn't - and 'Nazis are everywhere', basically, 'they are not just in Ukraine, NATO is full of Nazis'.
"I think he will try to move from his 'special operation'," Wallace told LBC Radio.
"He's been rolling the pitch, laying the ground for being able to say 'look, this is now a war against Nazis, and what I need is more people. I need more Russian cannon fodder'."
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What is the Victory Day parade?
Victory Day is a public holiday for Russians to remember those who were killed during the Second World War.
Troops parade across Moscow’s Red Square to mark the Soviet Union's role in the victory over Nazi Germany in 1945 and the Kremlin also shows off its military arsenal, including intercontinental ballistic missiles.
Last year, over 12,000 troops took part and more than 190 pieces of military hardware including over 80 military aircraft were displayed for all to see.
Putin usually oversees the pomp of the traditional march from an area packed with war veterans.
Russia's campaign in Ukraine is not going to plan, despite his claims to the contrary, Western nations have claimed.
Putin's forces attempted to take over the capital of Kyiv, but despite attempting an encirclement were forced out of the north/
Russia subsequently announced it was focusing its forces on the East of the country, and last week claimed to have seized the strategically important southern city of Mariupol having reduces swathes of it to rubble with a relentless bombing campaign.
But Ukrainian officials refuse to concede defeat, and hundreds of soldiers still remain in the last line of defence - the strategically important Azovstal steel works.