World leaders including North Korea's Kim Jong Un are gathering in China's capital for the showcase of Beijing's might on Wednesday.

"Our close communication reflects the strategic nature of Russian-Chinese ties, which are currently at an unprecedented level," Putin told Xi in remarks on a pooled live feed.

In a nod to cooperation between the two countries during the war, Putin said "we were always together then, and we remain together now."

Xi has embarked on a flurry of diplomatic meetings this week, including attendance at the Shanghai Cooperation Organisation (SCO) summit in the northern city of Tianjin -- a forum that China sees as an alternative to Western-dominated international cooperation.

The military parade on Wednesday marks 80 years since the end of World War II and will be attended by around two dozen world leaders.

- Global turmoil -

The Chinese and Russian leaders criticised Western governments during the summit on Monday, where Xi slammed "bullying behaviour" from certain countries -- a veiled reference to the United States, while Putin defended Russia's Ukraine offensive and blamed the West for triggering the conflict.

"China-Russia relations have withstood the test of international changes," Xi told Putin on Tuesday.

Xi added that Beijing was willing to work with Moscow to "promote the construction of a more just and reasonable global governance system".

Moscow and Beijing declared a "no limits partnership" shortly before Putin ordered Russia's Ukraine offensive in February 2022. The expanded military and trade ties since have troubled the West.

China has never denounced Russia's war nor called for it to withdraw its troops, and many of Ukraine's allies believe that Beijing has provided support to Moscow.

It insists it is a neutral party, regularly calling for an end to the fighting while also accusing Western countries of prolonging the conflict by arming Ukraine.

Xi and Putin are in regular contact and held a phone call last month, with the Chinese leader saying he was pleased to see Moscow and Washington improving their relations.

In May, Xi visited Moscow for Russia's May 9 celebrations of the World War II defeat of the Nazis.

China and Russia "have continued to deepen political mutual trust and strategic cooperation... and injected valuable stability and positive energy into an international situation full of interwoven turmoil," Xi said during his visit in May.