Russian President Vladimir Putin today vowed that "as in 1945, victory will be ours" as he congratulated former Soviet nations on the 77th anniversary of Nazi Germany's defeat in World War II.

"Today, our soldiers, as their ancestors, are fighting side by side to liberate their native land from the Nazi filth with the confidence that, as in 1945, victory will be ours," said Mr Putin, who sent Russian troops into Ukraine in February.

He also said he wished "all Ukraine's inhabitants a peaceful and just future".

The United Nations has confirmed 3,309 civilian deaths, including at least 234 children, in Ukraine since Russia invaded its ex-Soviet neighbor on 24 February.

The agency also reported 3,493 civilian injuries in the conflict so far.

The UN also estimates that over five million people in Ukraine have fled their homes since the war began.

Tomorrow, Moscow will officially commemorate victory over Nazi Germany with a giant military parade.

"It is our common duty to prevent the rebirth of Nazism which caused so much suffering to the peoples of different countries," said Mr Putin.

He added he hoped "new generations may be worthy of the memory of their fathers and grandfathers".

Mr Putin also made multiple references not just to soldiers but also civilians on the "home front... who smashed Nazism at the cost of countless sacrifices".

"Sadly, today, Nazism is rearing its head once more," charged the Russian president.

He has insisted that Ukraine is in the grip of fascism and a threat to Russia and the Russian-speaking minority in Ukraine's east which Moscow claims to be "liberating."

"Our sacred duty is to hold back the ideological successors of those who were defeated" in World War II, which Moscow dubs "the great patriotic war," said Putin, as he urged Russians to "take revenge."

Under President Putin, Russia has justified its offensive in Ukraine, launched on 24 February, as a "special operation" to "demilitarise" and "de-nazify" its neighbour, a former Soviet republic which declared independence in 1991.