Foreign Minister Sergei Lavrov said the ministers' discussions did not include the regional security group's enlargement in general either. The meeting had been expected to decide on whether to admit new members or set up mechanisms for a partnership dialogue for other countries to join.
Lavrov said the foreign ministers had agreed on arrangements, still to be approved at an SCO summit on August 28, for dialogue with any country interested in cooperation with the organization.
Asked whether the Islamic Republic would be invited to join the organization as an associate member, Lavrov said: "Iran cannot be an associate member as there is no such status at the SCO."
The SCO, comprising Russia, China, and four ex-Soviet Central Asian nations, has maintained a moratorium on new members for two years. Iran and Pakistan, observer states at the SCO since 2005, have sought full membership in the organization.
Western powers have been watching closely Iran's attempts to join the regional bloc, widely seen as a counterweight to NATO's influence in Eurasia.
Although Russia and China have major commercial interests in Iran, both nations have been cautious over admitting Iran, embroiled in a long-running dispute with the West and Israel over its nuclear program and alleged support for radical groups in Lebanon and other countries.