WASHINGTON -- The Bush administration on Friday softened its hard-line stance on how to thwart Iran's suspected nuclear arms program, agreeing to support a European plan that offers economic incentives for the Tehran government to give up any weapons ambitions.
Secretary of State Condoleezza Rice signaled, however, that Iran should move quickly or face the threat of harsh United Nations Security Council sanctions. The administration also privately expressed skepticism that Iran would live up to the bargain.
Until now, the administration has insisted that Iran deserves no reward for simply abiding by an international arms compact that forbids nuclear weapons development. The United States suspects Iran is using a legitimate program to develop nuclear power plants as cover for illegal weapons development.
"I'm pleased that we are speaking with one voice with our European friends," President Bush said during a trip to Shreveport, La.
"I look forward to working with our European friends to make it abundantly clear to the Iranian regime that the free world will not tolerate them having a nuclear weapon."
The United States agreed to drop opposition to Iranian membership in the World Trade Organization and to allow some sales of spare parts for civilian aircraft. If that carrot does not work, the Europeans agreed to support use of the stick the United States has unsuccessfully sought before: U.N. sanctions.
Rice said there is no timetable for negotiations, but added, "This has been going on for some time."
"I would think that if the Iranians are going to demonstrate that they are prepared to live up to their obligations, that they would want to do that sooner rather than later," she told reporters after meeting at the State Department with Ukrainian Foreign Minister Borys Tarasyuk.
"The Iranians need to take the opportunity that the Europeans are presenting them," Rice said.
The European Union warned Tehran explicitly about possible U.N. action Friday.
"We shall have no choice but to support referring Iran's nuclear program to the U.N. Security Council," a confidential EU document obtained by The Associated Press said.
There was no immediate response from Tehran.
It remains an open question whether Iran will surrender its right to both enrich uranium and reprocess it, said a senior administration official who briefed reporters on the condition of anonymity.
Still, added the official, the U.S. has made a move that could help the Europeans in their negotiations with the Iranians.
The shift places the United States side by side with British, French and German diplomats. Just weeks ago the Bush administration had seemed to write off their talks with Tehran as fruitless.
The change came about as Bush and Rice received personal assurances that the European countries negotiating with Tehran over its nuclear program are firmly committed to stopping any weapons program there, administration officials said Friday.
Both Rice and Bush discussed Iran during fence-mending trips to Europe in February. Those trips were meant to clear the air after disagreements with European powers during Bush's first term over the U.S.-led invasion of Iraq.
A dinner Rice attended in London with European Union foreign policy chief Javier Solana and counterparts from Britain, France and Germany was a key turning point, one official said on condition of anonymity.
At that March 1 dinner, the Europeans told Rice they would hold Iran to its obligations not to use civilian nuclear power programs to hide weapons research and development, and that the Europeans would support an international effort to invoke U.N. Security Council sanctions if Iran reneged, the official said.
Iran is building its first nuclear power plant with Russian help. The U.S. for now accepts Russian assurances that no enrichment or reprocessing will take place, and that spent fuel rods will be returned to Russia.
Weapons-grade nuclear fuel can be made either by enriching uranium or by reprocessing spent-fuel rods to create plutonium.
The European countries wanted U.S. support on the theory that a united front was most likely to persuade Iran to comply. So long as the United States remained apart, Iran would delay meaningful steps to end its nuclear program, the Europeans argued.
They also argued that the United States risked looking like the odd man out if the Europeans did win a nonproliferation deal. The Europeans urged the United States to join the talks, but the Bush administration wanted to remain at arm's length from Iran.
Iran and the United States have not had diplomatic relations since 1979, when Iranian militants occupied the U.S. Embassy in Tehran and held its staff hostage. The United States has long listed Iran as a state sponsor of terrorism.
Rice said in a statement that the administration will consider allowing the spare parts sales on a case-by-case basis. Many of the sales would be from European Union countries.
WTO membership increases a country's chances of selling goods to the United States and other rich nations. Joining can be a difficult process that takes several years.
Associated Press Writers George Jahn in Vienna, Austria, and Tom Raum in Washington contributed to this report.