Russia's President Vladimir Putin told officials at a meeting of the Shanghai Co-operation Organization that the group was "gathering momentum".
"It's an organisation that is... acquiring an increasing international weight," Mr Putin said.
Officials from China, Russia and parts of Central Asia are attending the Moscow talks, to discuss improving economic ties.
Observers from Pakistan, India, Iran and Mongolia are also present.
SHANGHAI CO-OPERATION ORGANIZATION
Security issues are expected to be a key issue on the agenda of the two-day meeting - and participating countries are also expected to sign economic and mutual emergency assistance agreements.
The group also seeks to act as a counterweight to the US.
In July, member states of Security Co-operation Organization, also known as the Shanghai Six, called for a deadline to be set for the withdrawal of US military bases from Uzbekistan and Kyrgyzstan.
Uzbekistan has since called on the US to leave before the end of this year.
Uzbekistan alarmed the US and other Western nations with a bloody crackdown on protesters in May, whom the government said were Muslim extremists but eyewitnesses said were civilians.
But Moscow and Beijing have staunchly backed Uzbekistan in the face of Western pressure.
As well as opening the Shanghai Co-operation Organization meeting on Wednesday, Mr Putin also held separate bilateral talks with Chinese Prime Minister Wen Jiabao.
Mr Putin praised the growing economic ties between Beijing and Moscow.