Russian leader Vladimir Putin said his ties with Chinese President Xi Jinping are at an "unprecedented level" as the two met in Beijing on the eve of a massive military parade.

Putin described Xi as a dear friend; Chinese state media said relations were exemplary. Russia is to increase supplies of gas to China, while Beijing will offer visa-free travel to Russians during a year-long trial.

Xi is also preparing to welcome North Korea's Kim Jong Un in what appears to be a show of solidarity with both aggressors in the Ukraine war.

Xi will host China's largest-ever military parade on Wednesday to mark the 80th anniversary of the formal surrender of the Japanese at the end of World War Two.

In May, Xi visited Moscow for Russia's celebrations to mark the defeat of the Nazis.

Russia and North Korea rely on China to bolster their economies, and these meetings will allow the Chinese leader to signal the extent of his power and influence – at a time when Donald Trump is trying to do a deal with Putin to end the war in Ukraine.

All three will stand shoulder to shoulder on Wednesday as tens of thousands of troops march through the Chinese capital.

At the talks in the Great Hall of the People on Tuesday, Putin made no explicit reference to his war in Ukraine, saying only that he had discussed issues of common concern with his Chinese counterpart.

"Dear friend, both I and the entire Russian delegation are pleased to meet once again with our Chinese friends and colleagues," Putin told Xi, according to a video published on the Kremlin's official Telegram messaging app.

"Our close communication reflects the strategic nature of Russia-China relations, which are at an unprecedentedly high level," he added.

"We were always together then, and we remain together now."

Xi told Putin that "China-Russia relations have withstood the test of international changes" - adding that Beijing was willing to work with Moscow to "promote the construction of a more just and reasonable global governance system".

This week's meetings come at a time when Xi seeks to project Beijing's power on the international stage - not just as the world's second-largest economy, but also as a diplomatic heavyweight.

Xi has emphasised China's role as a stable trading partner while US president Donald Trump's tariffs have upended economic relationships around the world.

Now, while a deal with the Russian leader to end the war in Ukraine continues to elude Trump, Xi's welcome of Putin to Beijing demonstrates their close ties.

The pair have previously touted their countries' relationship as a "friendship with no limits".

Russia hopes gas exports to China and other countries will replace revenue lost after Western sanctions were imposed over its Ukraine war.

Russian news agencies reported on Tuesday that once all projects are commissioned, the volume of pipeline gas supplies from Russia to China will amount to 106 billion cubic meters. That's still far below what Russia sent to the European Union before the full-scale invasion of Ukraine.

China's foreign ministry announced that it would extend month-long visa-free travel to Russian passport holders on a trial basis for a year, from 15 September.

Xi and Putin criticised Western governments at the Shanghai Cooperation Organisation (SCO) summit in Tianjin on Monday, while Putin defended Russia's Ukraine offensive and blamed the West for triggering the conflict.

In an apparent veiled reference to the US, Xi urged SCO members to "oppose Cold War thinking, bloc confrontation and bullying behaviour".

Putin said the summit - which was also attended by world leaders from India, Iran and Pakistan - had laid the foundations for a new system to replace "outdated Eurocentric and Euro-Atlantic models".

North Korea's leader Kim Jong Un will also attend the military parade on Wednesday, in what will be a landmark visit, after crossing the border into China on his special train early on Tuesday.

It is Kim's first multilateral international meeting. It is also the first time in decades that a North Korean leader will attend a Chinese military parade - the last time this happened was when Kim's grandfather, the founder of North Korea Kim Il-Sung, attended in 1959.

Most Western leaders are not expected to show up at the parade, due to their opposition to Russia's invasion of Ukraine, which has driven the sanctions against Putin's regime.

Beijing, however, has not criticised Putin's war. It has been accused by the US and its allies of aiding Russia's war effort - which Beijing denies - through its supply of dual-use materials and purchases of Russian oil.

Kim has supplied both weapons and troops to the Russian invasion.