Presidents Jiang Zemin of China and Vladimir V. Putin of Russia at their treaty signing in the Kremlin.

MOSCOW, July 16 — Russia and China signed a treaty of "friendship and cooperation" today, binding the two giants closer in the next 20 years and also committing them to oppose jointly much of the framework for international security that the United States is seeking to erect after the cold war.

Composed of 25 articles, the treaty joins Russia and China formally in opposing the United States' missile plans and places Russia more firmly behind China's claim of sovereignty over the island of Taiwan. It also strengthens military cooperation between Beijing and Moscow while rejecting the intervention that NATO undertook in 1999 in the Balkans to stop the killing of civilians.

The accord, sought by China, was concluded in a Kremlin ceremony with effusive gestures of camaraderie. The treaty bears the markings of a strategic pact that sets forth the deep concerns shared by Moscow and Beijing about a new world order dominated by the United States and its European allies. The agreement will quite likely be the center of discussion this week when President Bush and the leaders of the large industrial countries sit down with President Vladimir V. Putin of Russia at a summit meeting in Genoa, Italy.

One Russian commentator here described the treaty as "an act of friendship against America."

In Washington, the Bush administration played down the importance of the pact, saying it fell far short of cementing an alliance between the two countries. Officials said the accord had been in the works for a long time and was no surprise. [Article and excerpts, Page A8.]

Mr. Putin and President Jiang Zemin of China went to some length to explain that the accord, the first such agreement signed since the era of Stalin and Mao, was between neighbors that are seeking a new stability for Asian growth and development while carrying no content related to military alliance.

In a joint statement, the two nations said that they were hoping for a "just and rational new international order" and that the merger of their interests enshrined today were "not directed against third countries."

But in a striking similarity to the treaty politics of the cold war, in which Soviet leaders sought Presidents Richard M. Nixon and Gerald R. Ford to sign thinly disguised accords against China under Mao, the treaty signed today requires Moscow and Beijing to coordinate their response closely in the event that either is subjected to pressure or aggression from another power.

"If a threat of aggression arises," the treaty states, the two sides "will immediately make contact with each other and hold consultations in order to eliminate the emerging threat."

In addition, it elaborates on Mr. Putin and Mr. Jiang's opposition to the principle of humanitarian intervention, established in the NATO Balkan campaign to stop Serbian violence against civilians in Kosovo.

The pact says Russia and China "uphold the strict observance of generally recognized principles and norms of international law against any actions aimed at exerting pressure or interfering, under any pretext, with the internal affairs of the sovereign states."

For China, Russia's affirmation of Chinese sovereignty over Taiwan, now cemented in the more muscular confines of this treaty, follows the Bush administration's decision this year to sell an array of weaponry to the island, which has been estranged from the mainland for half a century.

"The government of the People's Republic of China is the sole legitimate government representing the whole of China" and "Taiwan is an integral part of China," the document states. The language is certain to cause alarm on Taiwan, where pro-independence leaders look to the United States to defend them against pressures from Beijing for reunification.

Russia is China's largest supplier for high-technology weaponry, as the United States is Taiwan's largest supplier under the terms of the Taiwan Relations Act of 1979, which binds Washington to provide adequate resources to the island so that it can defend itself in case of military pressure.

On missile defense, the two leaders said, "Russia and China stress the basic importance of the Antiballistic Missile Treaty, which is a cornerstone of strategic stability and the basis for reducing offensive weapons." Both countries "speak out for maintaining the treaty in its current form," the pact adds.

That last statement will complicate the Bush administration's strategy. Last week, it indicated that it would seek an agreement with Russia to allow the United States to conduct an aggressive program of testing missile defense interceptors and building missile silos and radar systems in Alaska without treating those tests as violations of the 1972 ABM accord.

In a news conference today that followed the signing of documents, officially called the Treaty on Good Neighborly Friendship and Cooperation Between the Russian Federation and the People's Republic of China, Mr. Jiang addressed the strategic dimensions of pact, saying an increase in cooperation between Beijing and Moscow would improve global stability.

"We believe that more active cooperation between our countries in discussing missile defenses and disarmament will enhance our efforts in building a multipolar world and establish a fair, rational international order," the Chinese leader said.

Mr. Putin agreed, and he seemed to be positioning himself to arrive at the summit meeting this week, where he is to meet Mr. Bush for the second time, as the spokesman for a larger constituency of countries disaffected with American leadership.

"We believe predictability in relations based on good neighborliness and legal ties" between Russia and China "will influence international affairs in a considerable and positive way," Mr. Putin said.

In a corollary to his summitry, Mr. Putin also more forcefully stated Russia's opposition to NATO expansion, a round of which is to be announced at a summit meeting in Prague in November 2002.

Speaking in an interview with the Italian newspaper Corriere della Sera, Mr. Putin said further expansion to Russia's borders would prolong the divisions of the cold war. "The problem should be simple," he said. "In the West, everyone says, `We don't want new divisions in Europe, we don't want new Berlin Walls.' Good. We completely agree."

"But when NATO enlarges, division doesn't disappear, it simply moves toward our borders," he said, complaining that NATO actions in Europe were free to pursue the political objectives of the Western alliance, even when there was no agreement in the United Nations Security Council for action.

"The divisions will continue until there is a single security area in Europe," he told the Italian newspaper. He suggested that just as the Warsaw Pact was disbanded, that NATO could, too, be disbanded in favor of a broader security structure, presumably one that included Russia. "But that is not even taken into consideration," he said.

In addition to the strategic dimension of the treaty, Russia and China formally agreed to reduce further military forces in border regions, fight terrorism and drug trafficking, work to resolve the final disputes along their 2,550 miles of border and prevent "groups" or third countries from using the territory of one country as a base against the other. They also agreed not to aim their strategic nuclear weapons at the other and said they would work to solve any dispute peacefully.

Though China is more ideologically aligned with Russia today, its trade routes lie elsewhere, especially to the United States, where trade volume was $115 billion last year, compared with less than $10 billion with Russia.

An important element of the accord, therefore, is to increase sales from the Russian oil, gas, nuclear and armaments industries, which Mr. Putin has been assiduously promoting in his diplomatic travels since taking office. The Tupolov airplane factory is hoping to take away a piece of the China market for passenger jets from Boeing this year with a 10-plane sale of TU-204 jets. And Gazprom, the Russian state energy giant, last week won a contract to lay a 2,400-mile gas pipeline to carry 20 billion cubic meters of gas a year from fields from the Xinjiang region in western China to Shanghai.

Mr. Jiang will make a visit to World War II memorials in Volgograd, site of the decisive Battle of Stalingrad, and then travel to Belarus, Moldova and Malta before returning home.