The United States on Friday ruled out any contact with Iranian delegates to an international aid conference that comes just before next week's showdown vote on whether to send Iran to the U.N. Security Council over its disputed nuclear program.

Secretary of State Condoleezza Rice leads a U.S. delegation to the two-day conference in London on international aid for rebuilding Afghanistan. On Thursday, the day after the session closes, the Vienna-based U.N. nuclear watchdog agency is set to vote on Iran's case.

"I do not anticipate, and I'm 100 percent sure about this, any contact between whichever official is sent by the Iranian government and our delegation, including Secretary Rice," said Undersecretary of State Nicholas Burns.

The no-contact policy holds even if Iran wants to talk about its nuclear program, Burns said. The United States has had no diplomatic relations with Iran since the 1979 storming of the U.S. Embassy in Tehran.

"In an environment where the new Iranian president has called for the destruction of Israel, has denied that the Holocaust happened as a historical fact, has put Iran on a more radical course on its nuclear policy, has continued Iranian support for terrorism, there's not a lot to talk about," Burns said.

Burns was referring to statements from Iran's hardline president, Mahmoud Ahmadinejad, which have alarmed even some of Iran's traditional allies and trading partners.

Iran is a next-door neighbor of Afghanistan, the former Al Qaeda redoubt whose Taliban leaders were ousted in a U.S.-led invasion in 2001. The United States has about 19,000 troops in Afghanistan but plans to cut the figure to about 16,500 by spring.

Burns is the department's No. 3 official and has led U.S. efforts to head off Iran's nuclear development or persuade other nations that the Tehran regime must be hauled before the Security Council for possible punishment.

Burns said he is confident that the U.N.'s International Atomic Energy Agency will hold a vote as scheduled Thursday, although key nations such as India and Russia seem to want to avoid going to the Security Council.

A majority of nations on the agency's 35-member board are already pledged to vote to refer Iran, Burns said. The United States has not said exactly what it wants the Security Council to do with Iran's case, but it hopes that the threat of sanctions, international ostracism or other penalties could sway Tehran.

Iran claims that its nuclear program is intended only to develop the know-how to produce nuclear energy. The United States and European allies argue that Iran is hiding a plan to build a bomb. The IAEA keeps tabs on the program but has little enforcement power.

IAEA chief Mohamed ElBaradei called on the United States on Friday to provide Iran with nuclear reactors and urged Tehran to declare a moratorium on enriching uranium for at least eight years. He spoke at a panel at the World Economic Forum in Switzerland.

India on Friday supported a plan to allow Iran to enrich its uranium in Russia and said that the world "should avoid confrontation and work in the spirit of seeking a mutually acceptable solution."

India did not say how it will vote at the Feb. 2 meeting.

The Russian proposal is meant to head off a confrontation that could lead to economic penalties against Iran, a major oil exporter.

The United States has been generally supportive of the Russian idea, which would take the most sensitive aspects of nuclear technology out of Iranian hands, but it claims that Iran is using the proposal to try to stall a Security Council vote.

The Senate approved a nonbinding resolution Friday supporting Security Council referral and calling on council members, particularly China and Russia, to act quickly. The resolution, approved on a voice vote, did not recommend what the Security Council should do.