The Chinese- and Russian-led Shanghai Cooperation Organization, or the SCO, has formally approved membership of Russia's ally Belarus.
The SCO Heads of State Council took place in Kazakhstan's capital Astana on Thursday following bilateral talks on the previous day.
Kazakh President Kassym-Jomart Tokayev, who chaired the meeting, said that by working together, the members had turned the SCO into one of the most influential and authoritative international structures.
He added that the world's interest in the organization is steadily growing.
Belarus was formally admitted to the organization as its 10th full-fledged member with Belarusian President Alexander Lukashenko in attendance.
Russia and China are apparently seeking to expand the organization as their own international framework to counter ones led by the United States and Europe.
Last year, Iran, which supports Russia's invasion into Ukraine, officially joined the framework.