ST. PETERSBURG, RUSSIA -- Russian President Vladimir Putin said Wednesday that Moscow's action in Ukraine was intended to stop a "war" that has raged in eastern Ukraine for many years.

Speaking at a meeting with veterans, Putin said that Moscow had long sought to negotiate a settlement to the conflict in Ukraine's eastern industrial heartland of Donbas, where Russia-backed separatists have been battling Ukrainian forces since 2014.

"Large-scale combat operations involving heavy weapons, artillery, tanks and aircraft haven't stopped in Donbas since 2014," Putin said. "All that we are doing today as part of the special military operation is an attempt to stop this war. This is the meaning of our operation -- protecting people who live on those territories."

On Wednesday, Putin again insisted that Russia had tried to negotiate a peaceful settlement before sending in troops, but "we were just duped and cheated."

He described Ukraine's east as Russia's "historic territories," adding that Moscow conceded their loss after the 1991 Soviet collapse but had to act to protect Russian speakers there.

Putin has explained his decision to send troops into Ukraine on Feb. 24 by the need to protect Russian speakers and conduct "demilitarization" and "denazification" of Ukraine to prevent it from posing a threat to Russia -- claims rejected by Ukraine and its Western allies as a cover for an unprovoked act of aggression.

Putin attended the meeting with veterans during Wednesday's visit to St. Petersburg to mark the 80th anniversary of the Red Army breaking the Nazi siege of the city on Jan. 18, 1943.

The siege of the city that was then called Leningrad lasted nearly 900 days and was only fully lifted in January 1944, marking one of the bloodiest pages of the Second World War. About 1 million people died in Leningrad during the siege, most of them from starvation.

Putin on Wednesday laid a wreath at the city's Piskaryov memorial cemetery where 420,000 civilian victims of the siege and 70,000 Soviet soldiers were buried. He also put flowers in a section where his brother, who died as a child during the siege, was buried in a mass grave.