Russia has rolled out an air defence missile system of the kind used to protect its base in Syria while jets screamed overhead in a showcase of its military war machine through Moscow's Red Square.

Key points: Grand parade marks victory over Nazis in World War II

Grand parade marks victory over Nazis in World War II Putin says commemoration is a symbol of closeness between Russia and its people

Putin says commemoration is a symbol of closeness between Russia and its people Parade highlights Moscow's modern military weapons and hardware

The grand parade, an annual fixture commemorating the Soviet Union's victory over the Nazis in World War II, took place in bright sunshine as President Vladimir Putin looked on from a tribune filled with Soviet war veterans, some of whom wore rows of campaign medals and clutched red roses.

The Russian leader, whose forces annexed Ukraine's Crimea in 2014 and are now helping Syrian President Bashar al-Assad's army, watched as thousands of troops marched across the cobbled square to the strains of martial music.

The authorities, backed by state media, use the event to encourage patriotism, reinforce national identity, for geopolitical point scoring, and to underscore the importance of having a strong military to protect the country's borders.

"It [the commemoration] has become a symbol of sacred closeness between Russia and its people," Mr Putin told the parade.

"And in such unity and loyalty to the motherland lies our strength, our confidence, and our dignity."

The Kremlin also now uses the event to show how a multi-billion-dollar modernisation program is changing the face of the Russian military with new weapons and hardware.

Some politicians in former Soviet republics or satellite states regard the parade as crude sabre-rattling by a resurgent Russia they say poses a threat to Europe's security.

Russia dismisses such allegations as nonsense.

Putin calls for unity in fighting terrorism

Thousands hold pictures of World War II soldiers during the Victory Day celebrations. ( Reuters: Sergei Karpukhin )

Columns of tanks followed the troops as did the advanced S-400 air defence missile system, which is deployed in Syria to protect the Russian air base there.

Russia's latest Yars mobile intercontinental nuclear missile launcher was also on show.

Scores of military aircraft flew over Red Square, including jets which emitted multi-coloured smoke to trace the red, blue and white colours of the Russian flag in the sky.

Mr Putin, in his speech, largely confined his remarks to the importance of the wartime victory.

But he also spoke of the need to fight global terrorism and to cooperate with other nations to do that.

"Terrorism has become a global threat. We must defeat this evil," Mr Putin said.

"And Russia is open to uniting efforts with other governments, is ready to work on the creation of a modern non-bloc system of international security."

State media criticised governments in Ukraine and Poland in the run-up to the parade for systematically dismantling wartime monuments in honour of Soviet forces, accusing them of dishonouring the troops who liberated them from the Nazis.

Ruling politicians in both countries disagree, saying Soviet troops were occupiers. The monuments are being pulled down as part of a de-communisation drive, they say.

Vladimir Norosov, 90, a Soviet veteran in Moscow for the parade, said he was angered by such remarks.

"We fought together, myself and my Polish brothers," he said.

"How many people died fighting to liberate that country? What they are doing now is disgraceful."

Russian Su-27 jet fighters and MIG 29 jet fighters fly over Moscow's Red Square. ( AFP: Kirill Kudryavtsev )

Reuters