WASHINGTON (AP) – In a major policy shift, the United States said Wednesday it will join other nations in holding direct talks with Iran on its nuclear program if Tehran first agrees to stop disputed nuclear activities that the West fears could lead to a bomb.

“Our message to the Iranians is that one, you won’t have a weapon, and two, that you must verifiably suspend any programs at which point we will come to the negotiating table to work on a way forward,” President Bush said Wednesday in responding to a reporter’s question.

“I thought it was important for the United States to take the lead _ along with our partners,” Bush said. “And that’s what you’re seeing. You’re seeing robust diplomacy. I believe this problem can be solved diplomatically and I’m going to give it every effort to do so.”

Secretary of State Condoleezza Rice said at the State Department that the United States will come to the negotiating table as soon as Iran fully and verifiably suspends its enrichment and reprocessing activities. She said the United States was taking the move to underscore its commitment to a diplomatic solution and to enhance prospects for success.

Asked at a news conference whether the United States would be willing to re-establish diplomatic relations with Iran, Rice ruled out a “grand bargain” and cited major disagreements between the two countries on many issues. However, Rice said a negotiated solution to the nuclear dispute could “begin to change the relationship.”

“We urge Iran to make this choice for peace, to abandon its ambition for nuclear weapons,” she said. At the same time, Rice acknowledged Iran has a right to civil nuclear energy.

The Swiss ambassador to the United States was called to the State Department earlier Wednesday to receive a copy of Rice’s remarks for transmission to Iran, U.S. officials said. 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 there for more than a year.

In Brussels, European Union foreign policy chief Javier Solana welcomed Rice’s remarks. “Direct U.S. participation would be the strongest and most positive signal of our common wish to reach an agreement with Iran,” Solana added.

British Foreign Secretary Margaret Beckett said European nations will offer Tehran “a serious and substantial” package to cooperate. “We are all striving to reach a diplomatic solution. The European side’s goal is to present a serious and substantial offer of cooperation, which demonstrates to Iran the benefits that would flow from compliance,” Beckett said, “rather than the further isolation which would result from their failure to do so.”

The Bush administration has been deeply suspicious of Iran’s intentions and the prime mover for tough United Nations action against the clerical regime. Until now, the United States has refused repeated calls from European nations, other diplomats and former secretaries of state to join the European talks.

For its part, Iran has for months refused to do what the U.S. is now demanding as a first step to talks _ suspend its enrichment of uranium, which Tehran claims is for peaceful purposes. Iran did voluntarily suspend those activities while talks were active with the Europeans last year, but resumed and stepped up those activities this spring.

Suspending uranium enrichment and related activities in order to talk with the United States would not preclude Iran from later insisting that it be allowed to continue those activities. At that point, the United States and its allies would be expected to move for tough U.N. Security Council action, possibly including economic or other sanctions.

Rice will meet with foreign ministers from the other permanent Security Council members on Thursday in Vienna to finalize a package of incentives and threats to be presented to Tehran.

“We hope that in the coming days the Iranian government will thoroughly consider this proposal,” Rice said.

European diplomats told The Associated Press that the package and the U.S. announcement of a willingness to talk were conditioned on pledges from Russia and China to eventually support tough actions such as sanctions if Iran continued to defy a U.N. call to stop its disputed activities.

“There must be a united international front that shares the same message, and that it that we’ll work collaboratively to prevent the Iranians from developing a nuclear weapon,” Bush said in the Oval Office.

“I also want to make it very clear that we respect the Iranian people and we respect their heritage and their history, and we hope their government listens to the international community, and doesn’t isolate itself from the world, and doesn’t foolishly spend money on a weapons program that takes away the capacity, the ability of the Iranian economy to grow so people are able to put food on the table and find work,” he said.

In recent weeks, Bush administration officials repeatedly have insisted there were no plans for one-on-one talks with Iran over its nuclear program, while holding open the possibility of such meetings on Iraq, where Tehran has substantial influence with that country’s Shiites.

U.S. allies and partners have pressured the Bush administration to engage Tehran directly, and Moscow and Beijing also are believed to support such a move.