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President Bush is putting Iran on notice "that we will not tolerate construction of a nuclear weapon."

With questions being raised about why such an oil-rich nation would need nuclear power, the president said Wednesday he doubted Tehran's (search) nuclear efforts were solely oriented toward energy production.

Asked how to stop Iran's leaders from building nuclear bombs, Bush characterized the battle as an international effort, not an American one.

"The international community must come together to make it very clear to Iran that we will not tolerate the construction of a nuclear weapon," Bush said from the White House Cabinet room. "Iran would be dangerous if it had a nuclear weapon."

The U.N.'s International Atomic Energy Agency (search) on Thursday urged Iran to "continue to be transparent" about its nuclear program and to drop objections to tougher inspections.

In a statement endorsed by the United States and other agency members, the IAEA board said it expected Iran "to grant the agency all access deemed necessary by the agency" to defuse suspicions that Tehran is operating a clandestine nuclear weapons program.

The statement also "encouraged Iran ... not to introduce nuclear material" at its Natanz enrichment plant pending the resolution of concerns about what it planned to do with any enriched fuel -- normally a component of nuclear warheads.

But Iran's envoy to the agency, Ali Salehi, told reporters that there was no consensus on whether Iran should unconditionally accept tougher inspections, and that only "some countries" on the board held that view, Reuters reported.

In Tehran, Iranian President Mohammad Khatami (search) said that his country was not trying to build nuclear weapons.

He said Iran would allow unfettered inspections by the nuclear watchdog agency but expected the international community to recognize Iran's right to acquire advanced peaceful nuclear technology.

"We confidently declare that we are not after nuclear weapons," Khatami said. "Actually we don't believe that atomic weapons can bring security to a nation against countries possessing this kind of weapons."

Speaking with reporters Wednesday, Bush also urged Iran's Islamic government to treat protesters there with "the utmost of respect."

Iran, which was cited by the U.N. nuclear weapons inspection chief for having "failed to report certain material and activities," is accused of having an advanced missile program while maintaining ties to terrorist groups, possibly including Al Qaeda (search).

The Bush administration says the conservative mullahs who run the country are deeply hostile toward the United States.

Bush has been the leading voice against Iran's nuclear pursuits, and has sought aid from the international community to pressure Tehran to drop its efforts.

The president has pressed Russian President Vladimir Putin (search) to halt construction of an Iranian nuclear power plant that could generate materials for a nuclear bomb. The Russians refused, but asked for stricter safeguards on nuclear materials.

The board of governors of the IAEA is meeting next week, and could find Iran in violation of the Nuclear Non-Proliferation Treaty (search), to which it is a signatory.

Bush has not said what his administration may do if Iran is in violation of the treaty, but has suggested that it wants to use a different approach than it has with Iraq and North Korea, the other two-thirds of the "axis of evil." (search)

Iranian officials pledged Wednesday to cooperate with the IAEA. The Bush administration is also counting on diplomatic pressure to encourage Iran to rethink its nuclear program, including taking the findings to the United Nations.

As for recent demonstrations by students against the Islamic government, Bush offered protesters a warm embrace.

"I appreciate those courageous souls who speak out for freedom in Iran. They need to know America stands squarely by their side," he said.

Violent clashes that began last week against clerical rule in Iran have for the most part died down in the last few days.

Presidential encouragement of protests and uprisings in other countries is tricky business. In 1991, former President Bush encouraged Iraqi Shiites in the south to rise up and overthrow Saddam Hussein. When they did, the United States failed to act and the Iraqi rebels were slaughtered.

That memory led to reluctance at the start of the Iraq war by Iraqi civilians who did not want to challenge Saddam's army or Republican Guard.

The Iranian government has accused Washington of interfering in its internal affairs -- and some opponents of the regime also say that public criticism by American leaders does not help their cause.

Reformist lawmaker Fatemeh Haqiqatjou said she and 200 other reformists signed a statement Tuesday against the U.S. comments. "Iranians want change and that change has to be brought by Iranians themselves, not foreigners," she said. "America's involvement only undermines the slow pace of reforms in Iran."

Fox News' Jim Angle and The Associated Press contributed to this report.