The leaders of China, Russia and four central Asian countries are meeting in Beijing to discuss the conflict of Afghanistan and other security issues.
The six members of the Shanghai Cooperation Organisation have been joined at the talks by leaders from Iran, Mongolia, India, Pakistan and Afghanistan.
Afghan stability is a "common concern", said Russian President Vladimir Putin.
Several meetings on the sidelines are also expected.
Mr Putin has had talks with China's President Hu Jintao.
The Shanghai Cooperation Organisation (SCO) group - including Russia and China and the central Asian states of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan - was formed in 2001.
Afghanistan has been invited to the meeting as a guest, while Iran, Mongolia, Pakistan and India are observer members.
"Strengthening political co-operation within the framework of the SCO must also strengthen co-operation in the economic sphere," Mr Putin said in an editorial in China's People's Daily newspaper on Tuesday.
The group was formed to curb extremism in the region and enhance border security. It was widely viewed as a countermeasure to curb the influence of Western alliances such as Nato.
The SCO then began to develop co-ordinated measures to stabilise their economies and maintain growth in Eurasia through multilateral trade and co-operation.
China said on Tuesday that the group was likely to give the go ahead for a plan to crack down on terrorism.
Nations attending the summit are also expected to further ties on the sides.
Afghanistan President Hamid Karzai is due to meet Mr Hu, as their countries are expected to announce ''a new strategic level" of relations, Kabul's foreign ministry said earlier.
The group meetings would likely discuss issues of stability and growth in Afghanistan as Nato forces prepare to pull out of the country.
Mr Putin will also meet his Iranian counterpart Mahmoud Ahmadinejad, ahead of talks hosted by Russia to seek diplomatic solutions over Iran's nuclear programme.
On Tuesday, China and Russia reinforced their opposition to foreign intervention in Syria and urged support for UN envoy Kofi Annan's peace plan.
Both countries have twice blocked UN resolutions critical of Damascus.
Beijing currently holds the UN Security Council's rotating presidency, and Russia and China have long resisted pressure to remove Syrian President Bashar al-Assad from power amid ongoing unrest.
Beijing and Moscow also signed a series of political and trade agreements.
''China is Russia's strategic partner. We enjoy mutually beneficial, mutually trusting, open cooperation in all fields," Mr Putin told reporters.
Mr Putin had said ahead of the trip that he wanted to further boost booming bilateral trade, which reached $84bn (£55bn) last year.