Chinese President Xi Jingping has praised the "unity" of the Shanghai Cooperation Agreement at the opening ceremony of the organization's summit in the coastal Chinese city of Quingdao.
Xi said on June 9 that the SCO "focuses on seeking common ground while setting aside differences and pursuing mutually beneficial cooperation."
The SCO is led by China and Russia, and includes Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, India, and Pakistan. Afghanistan, Belarus, Iran, and Mongolia have SCO observer status.
The current summit is the first to include India and Pakistan as members after they joined in 2017.
The main working day of the summit will be June 10.
Ahead of the summit opening, Russian President Vladimir Putin met with his Iranian counterpart, Hassan Rohani, to discuss the 2015 deal between Iran and leading world powers that restricted Iran's nuclear program.
The United States recently withdrew from the agreement and Iran was seeking a commitment from China, Russia, and European signatories to uphold the deal.
Russian Foreign Minister Sergei Lavrov told journalists that Moscow and Beijing have outlined a "roadmap" for the denuclearization of the Korean Peninsula.
He emphasized that the first step was to stop "belligerent rhetoric on both sides" and to convene multilateral peace talks.
"Everything is happening under the outline of the Russian-Chinese roadmap," Lavrov said.
The comments come just days before a historic summit in Singapore between U.S. President Donald Trump and North Korean Leader Kim Jong Un.
Putin also held a separate meeting with Xi and Mongolian President Khaltmaagin Battulga to discuss proposals to build oil and gas pipelines from Russia to China through Mongolia.
Putin said he supports the Mongolian proposal generally but said it needs further study.
Officials of the SCO also met with counterparts from the Collective Security Treaty Organization (CSTO) and the Commonwealth of Independent States (CIS), two other Russia-dominated Eurasian organizations.
The three organizations signed a memorandum of understanding on improving their "counterterrorism cooperation" and on creating "a joint approach" to countering drugs trafficking.
The next SCO summit will be held in Kyrgyzstan in June 2019.
with reporting by AFP, TASS, and Reuters