TEHRAN (Reuters) - Iran said on Wednesday it would welcome President Barack Obama's offer of a change in U.S. policy provided it involved a withdrawal of U.S. troops from abroad and an apology for past "crimes" against Tehran.
President Mahmoud Ahmadinejad was speaking after Obama offered to extend a hand of peace if Iran "unclenched its fist."
This marked a new approach from George W. Bush, who had sought to isolate Tehran, and Western diplomats said the change in Washington could offer a "once-in-a-generation" chance for the two foes to end three decades of hostility.
But the diplomats said that, while some pragmatic voices in Iran wanted better ties with the West, more hardline voices who control key levers of power could block an opening amid fears that Washington still wants to undermine the ruling system.
"We welcome change but on condition that change is fundamental and on the right track," Ahmadinejad told a rally in western Iran, broadcast live on state television.
"When they say policy would change, it means they would end America's military presence around the world," he said, referring to U.S. troops in Iraq, Afghanistan and elsewhere in the world.
Ahmadinejad said any change that was merely a shift in tactics would "soon be revealed."
"Those who say they want to make change, this is the change they should make: they should apologize to the Iranian nation and try to make up for their dark background and the crimes they have committed against the Iranian nation," Ahmadinejad said.
Any decision on U.S.-Iranian dialogue will require the approval of Supreme Leader Ayatollah Ali Khamenei, Iran's highest authority. He said in October that hatred of America ran deep in Iran and warned Iraqi leaders in January that U.S. governments could not be trusted.
The new U.S. administration has said Obama would break from his predecessor by pursuing direct talks with Tehran but has also warned Iran to expect more pressure if it did not meet the U.N. Security Council demand to halt its disputed nuclear work.
Washington and its Western allies accuse Iran of seeking to build nuclear weapons. Tehran denies the charge and refuses to give up work it insists is its sovereign right.
The Iranian president listed a range of "crimes" such as trying to block what Tehran says is a peaceful nuclear power generation program, hindering Iran's development since the 1979 revolution and other actions by several administrations for more than 60 years.
Ahmadinejad had harsh words for Obama's predecessor: "Mr Bush has gone into the trash can of history with a very black and shameful file full of treachery and killings."
"He left and, God willing, he will go to hell," he added.
A Western diplomat said Obama's election offered "a once in a generation opportunity" for a new start in relations between Tehran and Washington, which were cut after students seized the U.S. embassy in Tehran following the 1979 revolution.
"They will never get a new U.S. president who is as balanced as Obama's public statements are, who talks about wanting to engage in a respectful way with Iran and who seems less encumbered by the baggage of the past," the diplomat said.
"To me it is in Iran's clear interest to engage," he said, although he added there was a risk hardliners clinging to a "we're-winning-you're-losing rhetoric" may prevail.
Some ordinary Iranians, many of whom are tired isolation, voiced hopes that Obama's presidency would herald a new era but also said Tehran should tread cautiously.
"A golden opportunity is presenting itself, which will not always happen," said university student Negar Yazdani, 27, but added: "I believe the offer must be viewed with wisdom."
Mahmoud Abbasi, a 48-year-old taxi driver also speaking in the Iranian capital, was more hesitant. "We should not rush and accept direct talks without a plan and precaution," he said.
Iranian opposition politician Ebrahim Yazdi said he did not expect movement on the issue of U.S. relations before Iran's June vote, when Ahmadinejad is expected to seek re-election.
But he said better ties were in Iran's strategic and economic interest, adding: "The political atmosphere in Iran is now ripe, is suitable for direct negotiation with the United States."
Additional reporting by Hossein Jaseb and Fredrik Dahl, writing by Edmund Blair; Editing by Samia Nakhoul