Russian President Vladimir Putin evoked the memory of Soviet heroism in World War Two to inspire his army fighting in Ukraine, but offered no new road map to victory and acknowledged the cost in Russian soldiers' lives.

Addressing massed ranks of service personnel on Red Square on the 77th anniversary of victory over Nazi Germany, Putin condemned what he called external threats to weaken and divide Russia, and repeated familiar arguments that he had used to justify Russia's invasion on Feb 24 - that NATO was creating threats right next to its borders.

He directly addressed soldiers fighting in the Donbas region of eastern Ukraine, which Russia has pledged to "liberate" from Kyiv's control.

"You are fighting for the Motherland...