China welcomed world leaders as they arrived for the Shanghai Cooperation Organization (SCO) summit Sunday in Tianjin.
The two-day gathering will bring together leaders from more than 20 nations, including Russian President Vladimir Putin and Indian Prime Minister Narendra Modi.
The SCO comprises China, India, Russia, Pakistan, Iran, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan and Belarus, with 16 more countries affiliated as observers or "dialogue partners".
On Saturday, Chinese President Xi Jinping began receiving foreign leaders, including UN Secretary-General Antonio Guterres and Egyptian Prime Minister Mustafa Madbouly.
Others in attendance include Turkish President Recep Tayyip Erdogan and his Iranian counterpart Masoud Pezeshkian.
Modi in China after seven years
This is Modi's first visit to China since 2018. His talks with Xi come as relations between the neighbors show tentative signs of thawing after a 2020 border clash.
Recent tariff spats with the United States have served to bring the two rivals together.
Meanwhile, Modi on Saturday had a call with Ukrainian President Volodymyr Zelenskyy, in which the pair discussed restoring peace and stability in the region ahead of his key meeting with Putin.
Multiple bilateral meetings are expected to be held on the sidelines of the SCO summit.
Putin is expected to meet Erdogan to discuss the Ukraine conflict, while also holding talks with Pezeshkian on Iran's nuclear program.
Britain, France and Germany moved last week to reimpose UN sanctions on Tehran. Russia's Foreign Ministry on Friday warned that the reimposition of sanctions against Iran could lead to "irreparable consequences."
The summit will be followed military parade in Beijing marking 80 years since the end of World War II, with some 26 world leaders, including North Korea's Kim Jong Un, expected to attend.