Thousands of Russian troops marched through Red Square as Moscow put on a powerful show of patriotism and military might following its annexation of Crimea.
As Ukraine's crisis rumbled on with pro-Moscow rebels pushing ahead with independence votes, President Vladimir Putin praised Russian patriotism and loyalty to the state.
"This is a holiday when all-conquering patriotic force triumphs, when we all feel especially strongly what it means to be true to the Motherland and how important it is to be able to stand up for its interests," Putin told troops.
Russia's annual parade celebrating victory over the Nazis held special resonance this year amid the crisis in Ukraine, which has seen Russia annex Crimea and fighting in pro-Moscow areas in the east where separatists are threatening to break away.
Similar Victory Day celebrations were planned for later Friday in Sevastopol, with Russian media reporting that Putin could make a triumphant appearance at the Crimean port.
As dozens of helicopters and planes soared in the bright blue sky over Moscow, thousands of troops marched alongside tanks, mobile missile systems and armoured vehicles.
In contrast to the display of military hardware on Red Square, Ukraine planned muted Victory Day celebrations in a bid to avoid violence.
The head of Kiev's city council banned large-scale public gatherings or parades in the capital, fearing that the veterans could be attacked by "Russian provocateurs".
Ukraine's Prime Minister Arseniy Yatsenyuk said he fears recent softer comments from Putin are a prelude to provocation.
"I am concerned about Vladimir Putin's statement. It caused a bad feeling. They say one thing and do another. After this statement, I asked law enforcement officers to strengthen security measures on May 9," Yatsenyuk said.
On Wednesday, Putin stunned the world with an abrupt U-turn on Ukraine, calling on pro-Russian separatists in the east to delay independence referendums planned for this weekend and welcoming a May 25 presidential election.
But the rebels holed up in more than a dozen towns and cities in eastern Ukraine defied his plea and vowed to press ahead with referendums this Sunday that are bound to stoke tensions.
If Putin does head to Sevastopol, it will be his first visit to Crimea since the Black Sea peninsula was annexed by Moscow in March.
German Chancellor Angela Merkel on Thursday warned Putin against making the visit.
The crisis in Ukraine, which kicked off after the ouster of the country's pro-Kremlin president Viktor Yanukovych in February, has sunk Russia's relations with the West to their lowest point since the Cold War.
The United States and European Union have imposed a series of sanctions on Putin and his inner circle and EU ministers are to meet on Monday to consider further measures.
Fears of war on Europe's doorstep have been fired by fighting pitting Ukrainian troops against pro-Moscow gunmen in the east of the country, mainly around the town of Slavyansk.
Ukraine has lost 14 troops and three helicopter gunships with 66 servicemen injured in assaults on the rebels. The fighting has also claimed the lives of more than 30 insurgents.
Clashes that resulted in a horrific inferno in the southern port city of Odessa last week claimed another 42 lives, most of them pro-Russian activists, pushing the death toll over the past week to nearly 90.
The violence has prompted many Western politicians to warn that the country of 46 million people is slipping towards a civil war that would imperil peace in Europe.
