What you need to know:
- The celebration in Red Square also featured some 11,000 troops and more than 130 military vehicles, although a planned military flypast was cancelled.
President Vladimir Putin insisted Russia's war in Ukraine was necessary to defend the "Motherland" as Moscow flexed its military muscle at a parade marking the 1945 victory over Nazi Germany.
However, Putin's speech in Red Square made no major announcements on Russia's next steps in the invasion, despite reports that he could unveil an escalation or a general mobilisation.
Ukrainian leader Volodymyr Zelensky, whose forces are locked in battle with Russian troops in the east, used the occasion to say he would not allow Moscow to appropriate the Soviet Union's triumph in World War II.
Russia's ambassador to Poland was meanwhile splattered with a red substance in Warsaw when he tried to lay a wreath to mark Victory Day, in a sign of the international opposition to a war that is now in its third month.
The conflict is mired in the history between ex-Soviet neighbours Ukraine and Russia, with Putin saying the so-called "special military operation" in Ukraine is in part to "de-Nazify" the country.
Putin blamed the West and Ukraine for today's conflict, telling thousands of troops in Red Square that Russia faced an "absolutely unacceptable threat" and warning against the "horror of a global war".
"You are fighting for the Motherland, for its future, so that no-one forgets the lessons of the Second World War," he told Russian forces, shortly after intercontinental ballistic missiles rumbled through the square.
The celebration in Red Square also featured some 11,000 troops and more than 130 military vehicles, although a planned military flypast was cancelled.
'We will win'
On the ground, the key battles are being fought in Ukraine's east, which Russia is seeking to secure having tried and failed to take the capital Kyiv and the north.
An AFP team saw columns of trucks filled with soldiers and heavy equipment move down the main road leading away from the city of Severodonetsk, suggesting Ukraine was giving up the defence of its last stronghold in the eastern Lugansk region.
Russian forces were heavily shelling the roads, while the Ukrainians were firing back to help cover the apparent pullout.
Officials said 60 civilians were killed in a Russian air strike on a school in the eastern village of Bilogorivka on Sunday -- one of the highest single death tolls since the February 24 invasion.
Lugansk region governor Sergiy Gaiday said on Monday there were "very serious battles" around Bilogorivka and Rubizhne, as Russia tries to take the Russian-speaking Donbas.
Donbas encompasses Lugansk and the neighbouring region of Donetsk.
Zelensky, who spoke in a video address about an hour before Putin, had invoked the ghosts of World War II to chide Russia.
"We will not allow anyone to annex this victory. We will not allow it to be appropriated," he said.
Hailing what he said were Ukrainian victories against Nazi German forces during World War II, he said "We won then. We will win now."
'Free our land'
Yet in Kyiv the commemoration day was largely shunned as life slowly returned to normal, weeks after fierce fighting raged in its suburbs.
The capital’s Maidan square was largely empty. Small patrols of police and Ukrainian armed forces kept watch with air sirens temporarily disrupting the quiet morning, as people waited for any sign from Putin of an upcoming escalation.
"Whatever he says, we need to do what we need to win and free our land. And that's it," said retired diplomat Mykola, 75.
The West, which has hailed Zelensky as a hero, rallied behind Ukraine's defiance of Russia as the historical significance of Victory Day continued to resonate.
British Defence Secretary Ben Wallace accused Putin of "mirroring fascism" and said Russia's bemedalled generals should "face court martial" for their handling of the war.
French President Emmanuel Macron called for a "European political community" to host non-EU members like Ukraine. Brussels said it would give its opinion in June on Kyiv's bid to join the bloc.
However, in the latest in a series of visits by western officials, European Union President Charles Michel found himself having to take shelter from missile strikes during a surprise trip to Odessa.
In Warsaw, pro-Ukraine activists hurled red liquid at Russian ambassador Sergei Andreev and other men in his entourage at the cemetery of Soviet soldiers in the Polish capital
They chanted "fascists" and brandished the Ukrainian flag as they blocked his way, an AFP photographer at the scene said.
After wiping his face with his hand, Andreev said, "I am proud of my country and my president."
The fighting continued unabated on the ground.
In Severodonetsk, the easternmost city still held by Ukraine, a Ukrainian soldier with the nom de guerre Koval said that Russians had now entered its northern side.
"We are defending the southern half of the city," the soldier told AFP.
In the devastated southern port of Mariupol, depleted Ukrainian forces are defending their final bastion at the Azovstal steelworks.
Scores of civilians have been evacuated in recent days.
An AFP reporter in the city of Zaporizhzhia said on Sunday that eight buses carrying 174 civilians -- including 40 evacuated from the plant -- had arrived in that Ukrainian-controlled city.
Full control of Mariupol would allow Moscow to create a land bridge between the Crimean Peninsula, which it annexed in 2014, and eastern regions of Ukraine run by pro-Russian separatists.
One ray of hope has come from prisoner swaps.
Ukrainian soldier Glib Stryzhko, 25, was gravely wounded and captured in Mariupol in April but finally released after a secret phone call to his mother.
"After we were loaded onto the bus waiting for us, the driver said: 'Guys, you can breathe. You are home now,'" Stryzhko told AFP from his hospital bed in Zaporizhzhia.