"This notion that the United States is getting ready to attack Iran is simply ridiculous. Having said that, all options are on the table," he told a press conference at the end of a summit with European Union (EU) leaders.

Bush has repeatedly praised the diplomatic outreach by Britain, France and Germany, but paired it with increasing impatience at the Islamic republic's response and has steadfastly refused to rule out military force.

Washington wants to drag Tehran before the UN Security Council for possible sanctions, while the Europeans still hope to persuade Iran to comply with international obligations in return for a lucrative package of trade deals.

"Let me talk about Iran. That's a place where I'm getting good advice from European partners," Bush told reporters when asked whether he would commit to ruling out military action against Iran absent UN Security Council approval.

"Great Britain, Germany and France are negotiating with the ayatollahs to achieve a common objective, something that we all want, and that is for them (the Iranians) not to have a nuclear weapon," he said.

"These are great interlocutors on behalf of the position we share," said Bush, who famously branded Iran part of an "axis of evil" with North Korea and Saddam Hussein's Iraq in his 2002 State of the Union address.

Meanwhile, US officials had no reaction to French President Jacques Chirac's proposal that "a gesture" be made to Iran, perhaps linked to Tehran's desire to join the World Trade Organisation (WTO) or to obtain civilian aircraft engines.

And Bush, who leaves Brussels Wednesday to meet with German Chancellor Gerhard Schroeder, seemed poised to disappoint EU leaders who had hoped Washington might sign on as a full partner in the negotiations.

The United States has alleged that oil-rich Iran is using a civilian nuclear program to conceal efforts to acquire atomic weapons, a charge Tehran vehemently denies.

Iranian state media reported Tuesday that Tehran was willing to consider talks with the United States over Iran's controversial nuclear activities, despite the absence of diplomatic relations between the two countries.

"On the specific topic of the nuclear program, Iran is ready to enter into negotiations with the US to prove the civilian nature of the nuclear program," Mahmud Vaezi, deputy head of a studies institute affiliated to the foreign ministry, was quoted as saying by the IRNA news agency.

But amid tough US anti-Iranian rhetoric, the official stressed: "Iran has made it clear that normalization of relations with the United States depends on a tangible shift in the US attitude toward Iran."

The UN nuclear watchdog, the International Atomic Energy Agency (IAEA), which is leading efforts to bring Iran into line, has called on the United States to join the European effort.

Its head, Mohamed ElBaradei, recently told the German weekly Der Spiegel that the European efforts can succeed only "if the United States joins in and throws its weight behind it."

In television interviews ahead of his fence-mending trip to Europe, Bush rejected such suggestions, saying it gave the Iranians "excuses" for not bowing to European pressure.

"What they're trying to do is kind of wiggle out," he said of the Iranians on Germany's ARD television. "They're trying to say, 'well, we won't do anything, because America is not involved.'"

"But America is involved. We're in close consultation with our friends."

Some US allies and Bush critics say Washington's steadily increasing impatience with Iran reminds them of the crescendo before the war with Iraq.

"Iran however is different from Iraq," Bush insisted Monday. "We're in the early stages of diplomacy."

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