Russian President Vladimir Putin has condemned people who "desecrate memorials to war heroes", accusing them of sowing discord between nations.
Russia marks victory in World War II a day later than Western Europe
His comments at a Victory Day commemoration in Red Square appeared to be a continuation of a war of words with Estonia.
Estonia last month moved a Soviet-era war memorial out of the city-centre of the capital, Tallinn.
The move angered ethnic Russians in Estonia, and led to violent clashes.
One person was killed in the disturbances, and hundreds arrested.
Many Estonians consider the monument a symbol of the Soviet occupation, which continued for nearly 50 years after World War II, but for Russians it commemorates the Soviet Union's role in the victory over Nazism.
"The reasons for any war must be sought in the mistakes and miscalculations of peacetime, and their roots are in the ideology of confrontation and extremism," Mr Putin said.
He also warned of "new threats" based on "the same contempt for human life and the same claims of exceptionalism and diktat in the world as in the Third Reich", which correspondents interpreted as a criticism of US unilateral military action.
Some 7,000 soldiers marched on Red Square after Mr Putin's speech, and nine jet fighters flew overhead.
One thousand more soldiers took part in 2007, compared with 2006
Defence Minister Anatoly Serdyukov inspected the troops in an open Soviet-era Zil limousine.
The Estonian foreign minister has accused the Russian government of orchestrating the disturbances in Tallinn, and paying demonstrators to blockade the Estonian embassy in Moscow.
Russia, for its part, has accused Estonia of "indulging neofascists and inciting extremism".
In Belarus, President Alexander Lukashenko also criticised Estonia for moving the war monument, and lashed out against Poland too for failing to re-open an exhibition honouring Russian victims of the Auschwitz death camp.
"Acts of mockery of the heroes and victims of war give rise to anger and indignation," he told veterans.
"These include the dismantling of the monument to the liberators in Estonia, and the closure by Polish authorities of the Soviet exhibition at the Auschwitz camp museum."
He referred to Nato interventions in Afghanistan and ex-Yugoslavia as cases of "using war as an instrument of foreign policy".