President George W. Bush acknowledged on Monday that mistaken intelligence on Saddam Hussein's weapons program makes it more difficult to persuade the public that Iran's nuclear program poses a threat.

Speaking at a White House news conference, Bush said that when the United States tries to make its case on Iran, people will say "Well, the intelligence failed in Iraq; therefore, how can we can trust the intelligence in Iran?"

The United States is supporting efforts by Britain, Germany and France, known as the EU-3, to ensure that Iran doesn't develop nuclear weapons. Iran says its nuclear program is intended only to generate electricity.

Bush said that if diplomatic efforts fail, Iran could be referred to the UN Security Council for possible sanctions.

But he added "it's no question that the credibility of intelligence is necessary for good diplomacy."

Asked if he intended to make the case against Iran publicly, Bush said "the best place to make the case now is still in the counsels of government; in convincing the EU-3, for example, to continue working the diplomatic angle. Of course we want this to be solved diplomatically, and we want the Iranians to hear a unified voice."