The president's speech to thousands of soldiers and veterans on Red Square came at the start of an annual parade that sees hundred of pieces of military hardware roll through the streets of Moscow.

"The lessons of the past war are relevant once again. We have done and will do all that is necessary to guarantee the high capabilities of our armed forces," he said.

Those in the modern Russian army remember the "oath" of Soviet soldiers who fought Nazi Germany, he added: "I die but I will not surrender".

Putin asked the crowd to observe a minute's silence as the Kremlin clock chimed under grey skies.

Soviet leader Mikhail Gorbachev, 88, and Hollywood actor Steven Seagal, who has been a vocal supporter of Putin, were at the commemoration along with Russian dignitaries.

The two-day public holiday to celebrate the 1945 victory comes amid heightened tensions with the West and fears of a new Russia-US arms race.

Parades and celebrations took place in towns and cities across Russia, from the European exclave of Kaliningrad to the Far Eastern Sakhalin island, near Japan.

- Toy weapons -

In Moscow, flag-waving crowds lined the streets to catch a glimpse of tanks and personnel.

Among them were children dressed in miniature military uniform, a practice that has become popular in recent years but also sparked controversy.

Victory Day paraphernalia including replica soldiers' caps and toy weapons have been available to buy in Russian supermarkets in the days leading up to the event.

Thousands were also set to take part in the "Immortal Regiment" march, in which people carry pictures and medals of relatives who fought in the war.

Victory Day parades only became an annual event after the collapse of the USSR and the Immortal Regiment tradition began in 2012.

Since then the march has been heavily promoted in state media and city services offer to print out pictures of Soviet soldiers free of charge.

Almost half of Russians said they were planning to attend a Victory Day event this year, according to state pollster VTsIOM.

In recent years Moscow has stepped up military activity abroad, intervening on behalf of Bashar al-Assad's regime in Syria's civil war and backing separatist rebels in eastern Ukraine.

Around 750 personnel took part in a Victory Day parade at the Russian airbase in Syria's Hmeimim on Thursday, the defence ministry said in a statement.

Russia has also said it would build up its military presence in the Arctic, seeking to assert its influence in the strategic region.

State television broadcast marches from around the former USSR, including from the unrecognised republic of Lugansk -- a Ukrainian breakaway region run by the Moscow-backed separatists.

The conflict in eastern Ukraine has cost some 13,000 lives over the last five years.