By ITV News Multimedia Producer Elisa Menendez
Western officials have raised fears that Monday could be the day Putin drops the narrative that Russia is merely carrying out a "special military operation" and instead announce war with Ukraine, and by proxy with NATO given it has supplied weaponry.
The Kremlin has dismissed such reports as "nonsense" - but are officials right to be concerned?
What is May 9?
May 9, also known as "Victory Day" in Russia, is one of country's most important national holidays.
The symbolic day marks the Soviet Union's defeat of Nazi Germany in the Second World War in 1945.
How is Victory Day marked in Russia?
The day is marked by a large military parade in Moscow's Red Square, with Putin and other Russian officials traditionally standing on the tomb of former premier of the Soviet Union, Vladimir Lenin, to watch.
Other major cities across the country also host celebrations, parades, festivals and gather at memorials to commemorate fallen soldiers and the Soviet Union's suffering in WWII.
This year, which marks the 77th anniversary, more than 11,000 troops will take part in preparations, according to Russian media.
Emily Ferris, a research fellow specialising in Russia for the Royal United Services Institute (RUSI), said the Kremlin's core messaging of Victory Day has evolved over time.
She told ITV News: "It started off as commemorating the war. Over the years, especially under Putin's regime, what you're seeing more is it's an opportunity to rally people around collective Russian nationalism.
"But also, increasingly and cynically, it's an opportunity to display Russia's military prowess... to send a message externally to the West that this is Russia's capability."
"There is a very visceral collective memory of the Second World War. I think Victory Day is still quite dominant in terms of political narrative about why it's important for Russians to band together against an external enemy," she added.
"The main question now is whether Putin will use this as a springboard for something bigger."
Why is there fear Putin could use May 9 to declare war?
Since Russia invaded Ukraine on February 24, the Kremlin has insisted it is not at war with the country and is instead carrying out a "special military operation" - a claim dismissed by other countries.
President Putin has previously used May 9 celebrations to make statements against the West and this year, there are some clear parallels with Ukraine.
The Kremlin argues that one of the aims of the invasion is to fight neo-Nazism in the country and "liberate" its people - claims that have widely been dismissed as baseless.
Some have raised concerns Putin will mark the day by announcing a military escalation, or all-out war, which would allow him to introduce martial law.
Other possibilities are that he could announce mass mobilisation to replace what Western officials say have been significant troop losses, or declare a limited victory in Ukraine.
Ms Ferris analysed what each scenario could look like and how likely they are.
The expert said she has not seen "much evidence" yet that a war declaration or a military escalation is on the cards, nor is there "any particular need" for them, as society is not rebelling against the invasion and the standard of living has not considerably declined.
"The sanctions are having an immediate, short-term impact but it's not so substantive that you're seeing bread lines like the Soviet period," she continued.
"I'm not seeing that there is any collective push on the Russian people that requires Putin to make a big statement that would mobilise people in that way."
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Even if Putin was to declare war, it is doubtful how many more supplies Russia could commit to the front as "they're already quite overstretched" and have had few serious successes at capturing major cities.
"Even though there are all these suggestions that Putin is ill informed and people are nervous to report the truth to him, I think even he would know by now that the Russian resources are such that they would not be able to stretch their supplies even more thinly," added Ms Ferris.
Due to the dwindling supplies and depleted forces, mass mobilisation also looks unlikely, said Ms Ferris, as Russia would need to train new soldiers which would take months.
"You're not talking about a ready supply of young trained soldiers, you'd have to essentially call up civilians from the banking sector. So there wouldn't be any immediate value to the war effort," she continued.
"I think that would cause far more panic and Putin knows Russian society reasonably well."
But the expert says there is "far more evidence" to suggest Putin could declare victory in a limited way, perhaps by recognising some southern areas of Ukraine now under Russian control as "mini independent statelets" that are de facto controlled by Moscow - as he did with the regions of Donetsk and Luhansk shortly before the invasion.
"It's obviously something they've planned already," said Ms Ferris.
"They've taken quite a few steps - they've prepared draft documents about legislation, they're trying to introduce the Russian ruble into mainstream currency there, they're trying to set up their own puppet leader.
"All of this suggests that Russia is planning for a long-term political solution there rather than a military escalation."
Announcing a limited victory could also happen by declaring Mariupol has been "liberated", or that they have defeated "fascist entities" in parts of Ukraine, she added.
What has Russia said?
The Kremlin has rejected reports that President Putin could use the celebrations as a platform to formally declare all-out war with Ukraine, or any other form of escalation.
Kremlin spokesman Dmitry Peskov on Wednesday dismissed the suggestions as “untrue” and “nonsense”.