Tehran: The new US administration needs to show a "fundamental" change in policy not just tactics, Iran's president said yesterday after US President Barack Obama offered to extend a hand of peace to the Islamic Republic.

Obama, speaking in his first formal television interview as president, said his offer required Iran to "unclench its fist".

"We welcome change but on condition that change is fundamental and on the right track," Mahmoud Ahmadinejad told a rally in western Iran, broadcast live on state television.

"When they say 'we want to make changes', change can happen in two ways. First is a fundamental and effective change... The second ... is a change of tactics," Ahmadinejad said.

"It is very clear that, if the meaning of change is the second one, this will soon be revealed," he said.

The new 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 UN 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.

"Those who say they want to make change, this is the change they should make: they should apologise 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.

He listed a range of "crimes" such as trying to block what Tehran says is a peaceful nuclear power generation programme, hindering Iran's development since the 1979 revolution and other actions by several administrations for more than 60 years.

Iran has in the past told Washington that it should withdraw its troops from the region. Ahmadinejad, in his speech, said: "Who has asked them [the United States] to come and interfere in the affairs of nations?"

As well as saying Tehran wants nuclear arms, Washington accuses Iran of sponsoring "terrorists" and undermining efforts to make peace in the Middle East between Israel and Arabs.