Russia and China have vetoed a draft UN Security Council resolution that would have urged Burma to ease repression and release political prisoners.
Newly-elected Council member South Africa also voted against the measure.
Russia and China joined together in a rare double veto Friday to block a Burma resolution put forward by the United States and Britain.
The measure would have called on Burma's military government to stop persecution of political opponents and minority groups.
The sponsors were able to get the nine votes necessary to adopt a resolution in the 15-member Council.
France, Italy, Belgium, Slovakia, Ghana and Peru joined them in voting 'yes'. But South Africa joined Russia and China in voting 'no'.
Three other elected members, Indonesia, Qatar and Congo, abstained.
Acting U.S. Ambassador Alejandro Wolff expressed deep disappointment at the outcome.
Afterward, he spoke directly to Burma's people, urging them not to be discouraged.
Mr. Wolff said, "It is important to underscore that despite votes against by two permanent members, all members spoke about the situation in Burma. All of them recognized there are problems in the area of human rights, social issues, political freedom, and the people of Burma should not feel disheartened by this. This was an effort to bring this situation to attention of the world community and to send a clear signal that we haven't forgotten you and we won't forget you."
Friday's vote marked the first time Russia has used its veto since April, 2004, the first time China has exercised its veto since February, 1999, and the first time Beijing and Moscow have joined in a veto since 1972.
In casting their negative votes, the Russian and Chinese ambassadors argued that Burma, or Myanmar as it is known at the U.N., should not be on the agenda of the Security Council.
China's U.N. envoy Wang Guangya said the U.N. Charter gives the Security Council authority only in the case of threats to international peace and security.
Mr. Wang said, "Of course there are problems in Myanmar. But we believe these problems do not constitute a threat to regional or international peace and security."
Burma's U.N. Ambassador Kyaw Tint Swe said he was encouraged by the resolution's failure. He told the Security Council Burma has good relations with all other Southeast Asian nations.
Kyaw Tint Swe said, "Myanmar has close and cordial relations with all her five neighbors and other countries in the region and beyond. She does not engage in any activity aimed at undermining peace and security in any country."
Britain's U.N. Ambassador Emyr Jones-Parry said despite the resolution's defeat, he sees positive elements in the outcome.
Jones-Parry said, "It was quite clear in the statements made in the discussions, that we all share a deep concern about the plight of the beleaguered people of Burma/Myanmar. Concern about the lack of political progress, the poverty, the disease, the detentions, the fact that democratically-elected leaders are actually imprisoned, all those things are shared by members of the council."
The military has controlled Burma since 1962, shutting the country off from the outside world.
Thousands were killed when soldiers crushed a pro-democracy uprising in 1988.
After the country's military rulers suffered a crushing loss to pro-democracy leader Aung San Suu Kyi's party in 1990 elections, they ignored the results and remained in power.
International human rights groups have repeatedly called on the Security Council to act in response to Burma's deteriorating conditions.
The United States halted new American business investments there since 1997, and imposed a ban on financial transactions and imports in 2003.
Last week, 13 Nobel Peace Prize winners held a rally in Washington to call for the release of fellow laureate Aung San Suu Kyi.
She has been in detention for most of the past 17 years.
The United Nations estimates there are 11-hundred political prisoners in Burma.