Chinese President Xi Jinping and Russian President Vladimir Putin are scheduled to hold talks in Kazakhstan.
The meeting will take place on Wednesday in the Kazakh capital Astana, where a two-day summit of the Shanghai Cooperation Organization, a framework led by China and Russia, is scheduled.
Xi and Putin last met in Beijing in May. The Chinese side is expected to reconfirm its close ties with Russia as a way to counter the international order led by the US and Europe.
The Russian side is expected to emphasize its cooperative ties with China amid deepening rifts with Western nations over Moscow's invasion of Ukraine.
Last month, Putin visited North Korea and signed a new treaty that pledges mutual military assistance, if either of the countries faces invasion and is placed in a state of war. The focus is on how Putin will explain it to China, which has long been backing the North.
Earlier, Xi held one-on-one talks with Kazakh President Kassym-Jomart Tokayev who is chairing the summit.
Xi stressed the friendly relations between the two countries, saying he has an unwavering resolve to promote all-round cooperation no matter how the international situation may change.