MOSCOW — President Putin of Russia and his Chinese counterpart, President Hu, will attend an unprecedented show of joint military force Friday amid fears that the Russian leader is trying to turn an increasingly powerful central Asian alliance into a second Warsaw Pact.

The American government will be watching the military maneuvers anxiously from afar after its request to send observers was rejected. The maneuvers will be held under the auspices of the six-member Shanghai Cooperation Organization

Founded in 2001, the SCO, which includes the four central Asian nations of Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan as well as China and Russia, is rapidly gaining a reputation as an anti-Western organization.

That image seems to be one that Mr. Putin is happy to cultivate. Analysts say the Russian president believes the organization is emerging as a bloc that is rapidly becoming powerful enough to stand up to the West.

Russia’s most pro-government newspapers, often used by the Kremlin as propaganda vehicles, proclaimed the arrival of an “anti-Nato” alliance and a “Warsaw Pact 2.” At the annual SCO summit in the Kyrgyz capital Bishkek yesterday, Mr. Putin praised the alliance’s growing strength. “Year after year, the SCO becomes a more significant factor in strengthening security and stability in the central Asian region,” he said.

In a thinly disguised swipe at Washington, which mirrored earlier attacks on American “unilateralism” and “diktat,” he added: “We are convinced that any attempts to resolve global and regional problems alone are useless.”

For the most part, the summit’s agenda concentrated on promoting energy cooperation in central Asia, whose vast resources have elevated the region’s geopolitical importance.

The West has been desperate to strengthen its presence in the area but has begun to fall behind both Russia and China in a race for influence that has been compared to the 19th-century Great Game, when Britain and Russia competed for control of the region.

Yet the SCO has wider ambitions. Pakistan, India, and Mongolia all want to join — as does Iran, whose president, Mahmoud Ahmedinejad, attended the summit as guest of honor, a title bound to rile Washington. Iranian membership of the SCO would pose an enormous headache for the American government. Like Nato, its treaty states that an attack on one member is regarded as an attack on all, raising the prospect that the American government could find itself aligned against both Russia and China if it invaded Iran.