Russia has held a huge parade to mark 69 years since the Soviets defeated the Nazis.
Some 11,000 personnel were taking part in the parades
President Vladimir Putin told onlookers that the "iron will of the Soviet people" had saved Europe from slavery and vowed to defend the "motherland".
Unconfirmed reports say Mr Putin will visit a parade in Crimea later.
Festivities in Ukraine will be muted amid fears of provoking(刺激的) further violence in the south and east.
Moscow denies fomenting pro-Russian separatist unrest in Ukraine.
Mr Putin did not mention Ukraine in his speech.
He told the crowd that 9 May, known as Victory Day in Russia, was a "day of grief and eternal memory".
"It is a holiday when an overwhelming force of patriotism triumphs, when all of us feel particularly acutely what it means to be loyal to the motherland and how important it is to defend its interests," he said.
German Chancellor Angela Merkel said it would be a pity if Mr Putin were to use the commemorations to visit Crimea.
The parade in Moscow traditionally features a display of military hardware and a show of patriotic fervour(热情) on Red Square.