Russia will be a guarantor of world security, he said at the annual military parade on Red Square.
Putin made his short speech at the culmination of Victory Day, marking the defeat of Nazi Germany 68 years ago.
Moscow police say a man helping construct the stage for a major protest rally has died after a column of sound equipment collapsed.
Nadezhda Tolokonnikova, in custody since last March, may be deemed eligible for early release.
Since it began on May 7, Putin's third term in the Kremlin has appeared mostly defensive and downbeat.