UNITED NATIONS — An alliance between two of the five permanent members of the U.N. Security Council, Russia and China, that has endured through several recent world crises is faltering as the council clashes over the war in Georgia.

During a contentious public debate yesterday — in which Russia formally raised, for the first time at the council, its decision to recognize the independence of two separatist Georgian regions — China was one of the only seat holders in the 15-member body that did not ask to speak. Chinese diplomats also were mum during earlier closed-door consultations yesterday, as Russia tried, and failed, to convince council members to invite representatives of the two regions, South Ossetia and Abkhazia, to address the world body.

Chinese diplomats increasingly have raised their profile at council deliberations in recent years, and as the body deliberated over international crises this year in Sudan, Zimbabwe, and Burma, they have emerged as representatives of a true world power, using or threatening to use the veto power that they have mostly declined to wield in past decades.

“We will assess what they say, or whether they’ll maintain an eloquent silence,” the British ambassador to the United Nations, John Sawers, told The New York Sun as he entered the public session on Georgia yesterday, referring to China. Chinese diplomats then made no comment, even as other council members engaged in an increasingly contentious exchange.

“We have no complaint about the position taken by our colleagues,” Russia’s U.N. ambassador, Vitaly Churkin, said yesterday when asked about China’s lack of response at the council. But diplomats noted that China rebuffed President Medvedev’s appeal for support, made this week to a regional alliance of Central Asian countries, the Shanghai Cooperation Organization, of which China and Russia are members.

Tibetan separatists and Muslims from the western Chinese region of Xinjiang seeking independence present a major concern for Beijing. China also opposes U.N. membership for Taiwan, which it considers part of China. The conflict in South Ossetia also began just as the Olympic Games began in Beijing, reportedly raising the ire of Chinese officials.

Mr. Churkin said yesterday that officials from South Ossetia and Abkhazia, carrying Russian passports, have requested American visas at the American Embassy in Moscow so that they could come to address the Security Council. “They have not been refused,” he said, adding that such a denial would violate the host country agreement between America and the United Nations.

But according to several diplomats, Russia did not secure the requisite support of nine council members needed to invite the officials. “South Africa supported the Russians, and so did Vietnam, but China said nothing,” a Western diplomat, who spoke on the condition of anonymity, said.