"The moratorium has lasted for two years. We have now decided to consider the possibility of the SCO’s enlargement," a source in the Russian Foreign Ministry said.

Iran and Pakistan, observer states at the SCO since 2005, have sought full membership in the regional bloc comprising Russia, China, Kazakhstan, Tajikistan, Kyrgyzstan, and Uzbekistan and widely seen as a counterweight to NATO’s influence in Eurasia.

The group primarily addresses security issues, but has recently moved to embrace various economic and energy projects.

Russia and China 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.

Both China and Russia have major commercial interests in Iran. China wants Iranian oil and gas, and to sell weapons and other goods to the country, while Moscow hopes to sell more weapons and nuclear energy technology to Tehran.

The Kremlin also needs Iran’s endorsement for a multinational arrangement to exploit the Caspian Sea’s energy resources.

Other observers in the group are India and Mongolia.