Iran dismissed the offer as "a propaganda move."
Before leaving for meetings in Europe on Iran, Secretary of State Condoleezza Rice said that while the U.S. was willing to join talks between European nations and Iran, it was also helping to prepare a package of sanctions that Tehran could face should it decline the new offer.
"We're prepared to go either way," she said
At the White House, President George W. Bush said, "I believe that it's important that we solve this issue diplomatically, and my decision today says that the United States is going to take a leadership position in solving this issue."
The overture to join stalled European talks came after mounting pressure on the U.S. from European allies. The administration is convinced that Russia and China would support sanctions or other harsh measures if new talks fail to persuade Iran to abandon nuclear efforts that the West fears could lead to a bomb, a senior administration official said.
Rice will be working to reaffirm such support on Thursday, said the official, who briefed reporters only on condition of anonymity because the secretary was continuing talks with other countries.
The Iranian news agency said Iran accepts only proposals and conditions that are in the nation's interest. "Halting enrichment definitely doesn't meet such interests," IRNA said.
CBS News chief White House correspondent Jim Axelrod reports the United States has had no diplomatic ties with Iran and few contacts at all with its government since Islamic radicals took over the U.S. Embassy in 1979 and held diplomats for more than a year. In the recent showdown about Iran's nuclear ambitions, the Bush administration has given no signal a major shift was in the works and it was ready to engage Iran directly, Axelrod reports.
Rice will meet with foreign ministers from the other permanent U.N. Security Council members on Thursday in Vienna to finalize a package of economic incentives and threats to be presented to Tehran. That package would be on the table in any new talks involving the United States.