Leaders of China, Russia and four Central Asian republics have agreed to bolster their new security alliance. At a meeting in Uzbekistan, they pledged to support Afghanistan's efforts to maintain stability.

The leaders of the Shanghai Cooperation Organization were joined by Afghan President Hamid Karzai, whose nation has been a past launching point for extremist groups that have threatened Central Asia.

The Afghan leader attended the one-day summit as an observer and witnessed the Shanghai Cooperation Organization's formal establishment of its new anti-terrorism center in Tashkent. The leaders of the six-nation group pledged to increase their cooperation in fighting terrorism.

Some regional political analysts say the new center marks yet another step in the fledgling organization's evolution. China and others started the six-nation group in 1996 and formally established it in 2001 to deal with border security issues that erupted after the collapse of the Soviet Union.

A key topic of discussion at the summit was the drug trade, particularly the growing flow of opium out of Afghanistan. The group's leaders stressed that the drug trade is a global problem, one that could have serious implications for Central Asia's security and public health.

Matthew Oresman directs the China Eurasia Forum, a Washington-based research association. He said that the organization still has not accomplished much in concrete terms. "The greatest accomplishment it has had, in many ways, is that it is still alive," he said.

But Mr. Oresman also says the fact that it has established a headquarters in Beijing and drafted a charter indicate it is developing and may at some point attain some political clout.

China is the main force behind the organization, serving as host of its headquarters and its main financial contributor. President Hu Jintao announced Beijing will offer 900-million dollars in credit to member nations.

Mr. Oresman added that this offer is in line with China's deep interest in maintaining stability in its western region, which is home to Muslim separatist movements led by members of the ethnic Uighur group. "China's fear is that Central Asia will become a base of operations for a Uighur resistance movement; that Uighurs living in Central Asia will support internal instability in China, and China is very interested in making sure this doesn't happen," he explained.

Member nations also agreed to allow Mongolia to participate as an observer.

Russia and Uzbekistan, the most populous country in Central Asia, signed a military cooperation agreement and an oil exploration deal on the sidelines of the meeting.