The giant, annual Victory Day parade is under way, for the first time including missiles adapted for Arctic warfare.
Russia is developing new Arctic bases.
"No force will be able to dominate our people," Mr Putin said, deploring the havoc that Nazi Germany wreaked in the war. The USSR lost more than 20 million people - more than any other country.
The Soviet Union (USSR) ceased to exist in 1991.
The military hardware on show in Red Square on Tuesday includes Pantsir-SA air defence missiles in grey-white Arctic camouflage, Tass news agency reports.
Yars intercontinental ballistic missiles, which deliver nuclear warheads, have also trundled past the assembled military top brass, government officials and bemedalled war veterans.
Members of a new "military-patriotic" youth movement, called Yunarmiya, are also participating in the parade for the first time.
The main event is in Moscow, but parades are also taking place in cities across Russia, many of which were devastated in the 1941-1945 bloodbath that Russians call the "Great Patriotic War".
"To fight terrorism, extremism and neo-Nazism we need the co-operation of the entire world community," Mr Putin said in his short speech.
Russia has deployed many of its latest weapons in the Syrian war, backing President Bashar al-Assad's forces, who are also heavily assisted by Iran.