BRASILIA, Brazil: Brazil rebuffed a US appeal for new sanctions on Iran over its nuclear program, vowing during a visit from US Secretary of State Hillary Rodham Clinton not to "bow down" to gathering international pressure.

Brazilian President Luiz Inacio Lula da Silva pre-empted Clinton even before she could make the case for new United Nations Security Council penalties. Silva is an outspoken opponent of sanctions, and his country currently sits on the Security Council, which will be asked to approve its toughest-ever penalties on Iran later this year.

Clinton told a news conference she respects Brazil's position but thinks if there is any possibility of negotiating with Iran, it would happen only after a new round of sanctions.

Iran has accelerated its disputed nuclear program in the face of previous UN penalties, but the United States and other supporters say a renewed demonstration of world resolve could finally push Iran to the bargaining table.

"The door is open for negotiations. We never slammed it shut," Clinton said. "But we don't see anybody, even in the far-off distance, walking toward it."

The Obama administration took office last year pledging to reach out to Iran and make the case that Tehran had more to lose than gain from pressing ahead with nuclear development that much of the world suspects is aimed at building a bomb.

Yet the administration has done an about-face after a frustrating year that saw nuclear gains by Iran with no sign the country is interested in serious talks with Washington. The two countries have been estranged since the 1979 takeover of the US Embassy in Tehran, and there is almost no economic or diplomatic contact between them.

Iran does have vast business and other ties with most of the rest of the world, and Clinton said the oil giant is exploiting its relationships to try to avoid new UN penalties.

"We see an Iran that runs to Brazil, an Iran that runs to Turkey, an Iran that runs to China, telling different things to different people," Clinton said angrily.

Standing with her at a press conference in the Brazilian capital, Foreign Minister Celso Amorim was not persuaded.

"We will not simply bow down to an evolving consensus if we do not agree," Amorim said. "We have to think by ourselves and with our values and principles."

Clinton told Congress last week she expected new sanctions were only 30 to 60 days away, but on Monday she seemed to roll back the timeline, saying she thought they would be considered "in the next couple months."

Iran already is under three sets of UN Security Council sanctions for refusing to stop uranium enrichment - a potential pathway to nuclear weapons _ and other activities, generating concerns that it seeks to build a bomb. It insists it is enriching only to make nuclear fuel for an envisaged reactor network.

Another round of sanctions could pass without Brazil's vote. But the United States and other backers of new sanctions want as wide a backing as possible to show Iran that its behavior is costing it friendships around the globe.

Sanctions, Clinton said, "are the best way to avoid problems like conflict and arms races that could disrupt the stability, the peace and the oil markets of the world."

Silva, who hosted Iranian President Mahmoud Ahmadinejad in Brazil last year, said he did not want to see Iran develop nuclear weapons and would raise the matter when he travels to Tehran in May. Silva said he would have a "frank" conversation with Ahmadinejad about Iran's nuclear program.

"I want for Iran the same thing I want for Brazil: to use the development of nuclear energy for peaceful purposes," he said. "If Iran agrees with that, Iran will have the support of Brazil."

And he added that if Iran "wants to go beyond" pursuing nuclear power for peaceful purposes that Brazil would oppose its program.