President Bush says the world must speak with one voice about Iran's nuclear ambitions and that Tehran should realize its continued defiance will lead to sanctions. Mr. Bush spoke at the end of talks with Israeli Prime Minister Ehud Olmert.

Iran is a major concern for both the United States and Israel.

Iranian leaders have vowed to destroy Israel, and Iranian nuclear ambitions are a top security issue for the Jewish state.

President Bush has advocated a multilateral approach to the problem. And when reporters were brought in at the end of his meeting with Prime Minister Olmert, the president raised the prospect of U.N. sanctions, should Iran proceed with uranium enrichment activities.

"I think it is very important for the world to unite with one common voice, to say to the Iranians, if you choose to move forward, you will be isolated," said President Bush. "One form of isolation would be economic isolation."

The president stressed Iran must realize it will pay a price for its intransigence.

"A lot of the world has made it clear that the Iranian nuclear weapons ambitions are not in the world's interests," he said. "And therefore, if they continue to move forward with the program, there has got to be a consequence."

Iran says its nuclear program is purely civilian in nature, and designed to meet the nation's civilian energy needs. But the United States and many of its allies maintain the program is likely to be a cover for the development of nuclear arms.

Britain, France and Germany have tried to negotiate a settlement with Iran, and Russia has offered to provide and monitor the nuclear fuel needed for Iranian nuclear power plants so there would be no need for Iran's government to enrich uranium.

But the Iranians have been resistant, and President Bush warns that if Iran does produce nuclear weapons, that would have a destabilizing effect throughout the Middle East.

"I say this in the interest of world peace, if Iran has a nuclear weapon, it will be incredibly destabilizing and obviously threatening of our strong ally [Israel]," noted President Bush. "And so my attitude is, let's work in concert to convince the government [of Iran] that it is just not the Israeli voice speaking or the United States voice speaking, but there are a lot of other voices saying the exact same thing."

During a session with reporters, the president rejected direct talks with Iran, saying the United States will engage in dialogue only if Iran follows through on U.N. demands to suspend uranium enrichment.

Prime Minister Olmert said he shares the president's views on Iran. Earlier, during an appearance on NBC television, the Israeli leader said he hoped efforts to resolve the matter diplomatically would yield results, adding he is not looking for war.

"Every compromise that will stop Iran from acquiring nuclear capabilities, which will be acceptable to President Bush, would be acceptable to me," said Ehud Olmert.

Mr. Olmert was asked if his country might consider a preemptive strike on Iran's nuclear facilities. He responded by saying he hopes the situation will not reach that stage, but he stressed Israel will not tolerate a nuclear armed Iran.