The U.S. and Canada challenged Iran's claims that hard-liner Mahmoud Ahmadinejad won re-election, but much of the rest of the world remained silent Saturday despite claims of fraud and scenes of clashes on the streets of Tehran.

For the Middle East and West alike, the stakes were high.

Iran is a key economic player in the region, a perceived threat to Israel's national security — and a major worry for the U.S. and allies who fear Tehran is trying to build a nuclear weapon.

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Supporters of pro-reform candidate Mir Hossein Mousavi alleged that the outcome was rigged and clashes erupted in Tehran and at least one other city after Ahmadinejad's government declared him the victor in a landslide. The U.S. refused to accept Ahmadinejad's claim of a landslide and Secretary of State Hillary Rodham Clinton said she hoped the outcome reflected the "genuine will and desire" of Iranian voters.

"We are monitoring the situation as it unfolds in Iran, but we, like the rest of the world, are waiting and watching to see what the Iranian people decide," Clinton told reporters during a visit to Canada.

Canadian Foreign Affairs Minister Lawrence Cannon said his country, too, was "deeply concerned" by reports of irregularities.

British Foreign Secretary David Miliband said concerns about ballot counting that candidates have expressed are an issue for Iranian authorities to address. "Our priority is that Iran engages with the concerns of the world community, above all on the issue of nuclear proliferation," he said.

But most countries appeared to be taking a wait-and-see approach, including the European Union and China, Germany, Italy and Japan — nations with strong economic ties to Iran.

France said it was closely following the situation.

Ahmadinejad blasted foreign media coverage of the election, saying, "This is a great victory at a time when the ... propaganda facilities outside Iran and sometimes inside Iran were totally mobilized against our people."

"The heaviest pressure and psychological warfare was organized against the people of Iran. A large number of foreign media ... organized a full-fledged fight against our people," Ahmadinejad said, according to an English translation of his victory speech carried on state television.

About 200 Iranians protested outside the Iranian Embassy in London. Hadi Ghaemi, spokesman for the International Campaign for Human Rights in Iran, denounced the outcome as "a Tehran Tiananmen" — a reference to China's brutal 1989 crackdown on pro-democracy activists — and urged the international community not to recognize the result.

President Obama has offered dialogue with Iran after a nearly 30-year diplomatic freeze between the two nations. Iran insists its nuclear program is peaceful and geared solely toward generating electricity; U.S. officials contend it's trying to enrich uranium to weapons grade.

Privately, many diplomats at the International Atomic Energy Agency — the Vienna-based U.N. nuclear watchdog — said they expected little change regardless of who wound up in charge of Iran's government.

That's because Iran's main policies and any major decisions, such as possible talks with Washington or nuclear policies, rest with the ruling clerics headed by Iran's unelected supreme leader, Ayatollah Ali Khamenei.

"On the nuclear question, it's very clear that the ultimate decision maker is Ayatollah Khamenei," said Mohsen Milani, an expert on Iran at the University of South Florida. At best, he said, Ahmadinejad plays a subtle and nuanced role.

"The central question of security or war and peace is not in his domain. It's unambiguously in the domain of the supreme leader," Milani said.

And more Ahmadinejad spells less change, said former President Jimmy Carter.

"I don't think it will have any real effect because the same person will be there as has been there," Carter said after meeting with Palestinian Prime Minister Salam Fayyad in the West Bank city of Ramallah. "I think this election has bought out a lot of opposition to his policies in Iran, and I'm sure he'll listen to those opinions and hopefully moderate his position."

Ahmadinejad's new mandate may allow Israel to briefly deflect U.S. pressure to endorse the creation of a Palestinian state and freeze the construction of Jewish settlements in the West Bank, said Yossi Alpher, a former intelligence official and government adviser.

Ahmadinejad has outraged Israelis and many others worldwide by publicly challenging the Jewish state's right to exist.

"The re-election of Ahmadinejad demonstrates the increasing Iranian threat," said Danny Ayalon, Israel's deputy foreign minister.

Arab League chief Amr Moussa said he hoped Ahmadinajad's second term would boost cooperation to achieve peace and rid the region of weapons of mass destruction. "I believe the situation could move in the direction of quieter talks and understanding. Dialogue is the name of the game," he said.

Iraq's government said it hoped the Iranian leader will seek reconciliation with other countries to promote peace in the region.

Iraq's Shiite-led government faces a delicate balancing act in maintaining close ties to both the U.S. and Iran.

"We hope that the new term of the Iranian president will begin a period of reconciliation with all countries that have no friendly relations with it," spokesman Ali al-Dabbagh said Saturday in a clear reference to the U.S.

Dawood al-Shirian, a prominent Saudi columnist, said Ahmadinejad's win "won't necessarily be a bad thing" for Saudi Arabia and the rest of the Gulf. "There are open channels with Ahmadinejad. They know him, and it's better to deal with someone they know," said al-Shirian.

Mousavi, Ahmadinejad's opponent, had advocated closer Iranian ties to the U.S. Perhaps not surprisingly, Venezuelan President Hugo Chavez — a frequent critic of U.S. foreign policy — rushed to declare his support for the incumbent.

"In President Mahmoud Ahmadinejad we have one of the greatest allies on this earth," Chavez said at an oil summit in the Caribbean.

Syrian President Bashar Assad congratulated Ahmadinejad and "expressed his confidence in continuing friendly relations and strengthening cooperation," Syria's official news agency SANA reported.