MOSCOW -- Bouquet in hand before the Eternal Flame at the Red Square, Chinese President Xi Jinping joined Russian President Vladimir Putin and more than 20 other leaders to lay red flowers at the Tomb of the Unknown Soldier.

The solemn ceremony marked a moment of remembrance and tribute to those who perished in the Soviet Union's Great Patriotic War, as Russia celebrated the 80th anniversary of victory in that war on Friday.

This year's commemorations culminated in a grand military parade at the Red Square earlier in the day. At the main viewing stand, Xi and Putin sat side by side and talked from time to time.

Over 11,500 military personnel, including contingents from more than 10 countries, took part in the parade. Among them was the Guard of Honor of the Chinese People's Liberation Army (PLA). Xi rose from his seat when the PLA unit passed through the square.

In the parade's "historical" segment, Russian service members, clad in uniforms from the era of the Soviet Union's Great Patriotic War, carried vintage military flags and weapons, evoking memories of the years of resistance against Fascism.

On the night of May 8, 1945, Germany signed the surrender document in Karlshorst, Berlin, marking the end of WWII in Europe. Meanwhile in Moscow, it was already May 9, which was designated by the Soviet Union and later Russia as "Victory Day." Since 1995, Russia has been holding military parades and other commemorative events every year on May 9.

"The Soviet Union took upon itself the most ferocious, merciless blows of the enemy," Putin said in an address ahead of the parade. "We shall always remember that the opening of the Second Front in Europe after the decisive battles on the territory of the Soviet Union brought victory closer."

"We highly value the contribution to our common struggle of Allied soldiers, members of the resistance, the courageous people of China, all those who fought for a peaceful future," Putin said.

The Soviet Union was the principal theater of World War II in Europe, losing 27 million lives, while China was the main theater in Asia, suffering 35 million casualties in its resistance against the bulk of Japanese militarist forces. Together, the two countries served as the mainstay of resistance against Japanese militarism and German Nazism, making pivotal contributions to the victory in the World Anti-Fascist War.

Eighty years ago, in the face of brutal aggression of militarism and Nazism, the Chinese and Russian peoples stood united, fighting side by side against a common enemy and writing a remarkable and heroic chapter in history, Xi said when he and Putin jointly met the press on Thursday after their talks at the Kremlin.

This is the second time for Xi to attend Russia's Victory Day celebrations after he traveled to Moscow upon the 70th anniversary 10 years ago. That same year, Putin also attended China's Victory Day parade on Sept. 3 in Beijing to commemorate the victory of the Chinese People's War of Resistance against Japanese Aggression and the World Anti-Fascist War.

The past decade has been one of profound turbulence and transformation in the international landscape, Xi noted when meeting the press with Putin on Thursday.

In the face of the changes of the world, of the times and of historical significance, China and Russia should keep a firm grasp on the development direction of bilateral ties and the general trend of the development of human society, Xi said, calling for greater joint efforts in safeguarding international fairness and justice.

Ahead of his state visit to Russia, Xi published a signed article in Russian media titled "Learning from History to Build Together a Brighter Future."

"Indeed, historical memory and truth will not fade with the passage of time. They serve as inspirations that mirror the present and illuminate the future. We must learn from history, especially the hard lessons of the Second World War," he wrote.