SCO Secretary General Bolat Nurgaliyev said at a Moscow-Beijing video conference that members disagree about whether to add more states, the Russian news agency RIA Novosti reported.
India, Iran, Mongolia and Pakistan have observer status, and Pakistan also has applied to become a full member. The current membership includes Russia, China and the central Asian states of Tajikistan, Kyrgyzstan, Kazakhstan, and Uzbekistan.
Tajikistan is the current president.
The organization, conceived as a counterweight to NATO, is mostly concerned with defense issues and now with energy.
A meeting of the member-nation heads of states is scheduled for August in Tajikistan.