First and foremost, the Islamic republic's leadership appears confused over Washington's intentions -- were they a tentative step toward dialogue or just amount to a small role in what has been a massive international relief operation?

"The Americans themselves have declared that the action is not political but humanitarian," said Hassan Rowhani, a top cleric who heads Iran's Supreme National Security Council.

"When a nation is faced with a tragedy, other nations rise to their support and show solidarity, and we cannot but expect this," he said, before adding that "expressions of solidarity and condolences can alter the course of history in relations between nations".

Iran and the United States cut diplomatic ties after the 1979 Islamic revolution saw the US-backed shah overthrown and 52 Americans held hostage at the American embassy here for 444 days.

And Iranian officials are still reeling from US President George W. Bush's 2002 speech in which he lumped the Islamic republic into an "axis of evil" along with Saddam Hussein's Iraq and North Korea.

Bush has also qualified the aid by renewing calls for Iran to abandon its alleged efforts to develop nuclear weapons and hand over detained members of Osama bin Laden's Al-Qaeda network.

Rowhani, seen as a moderate conservative, emphasised that relations between the two old enemies were "complicated" and asserted "the key to resolving these issues is in the hands of the US government."

He pointed to the continued presence in US-occupied Iraq of the People's Mujahedeen -- an armed Iranian opposition group -- as one matter the United States could resolve.

"In recent days we have heard different voices, so by consequence it is difficult to judge. It is not clear if this gesture is isolated or not," said foreign ministry spokesman Hamid Reza Asefi on Sunday.

"The US knows what it has to do. Political and humanitarian questions should not be mixed."

In addition to sending aid supplies and a medical team, Washington approached Tehran about the possibility of sending a delegation headed by top Republican Senator Elizabeth Dole -- possibly accompanied by a member of Bush's family.

Washington's unilateral sanctions against Iran -- which cost the country billions of dollars each year -- have also been partially suspended for three months following the December 26 disaster which killed at least 30,000 people.

Iran has said the "time is not right" for such a visit, which would have been the first public official US trip to the Islamic nation since the revolution.

Analysts, however, point to forthcoming parliamentary elections here and the fact that the regime continues to partially define itself by its opposition to the "Great Satan" -- as the United States is referred to in hardline circles in Iran.

This had led to what appears to be an incapacity to address the issue seriously, and the latest US gesture -- the first tangible sign of a willingness to talk from the Bush administration -- has raised calls for Iran's leaders to rethink their rhetoric.

Mohsen Mirdamadi, a reformist who heads the parliamentary commission on foreign affairs and national security, asserted that Iran "needs to repond to these positive steps" by Washington.

"We should not, with cliched replies, waste this opportunity and should profit from the current climate to move in the direction of trust and detente."

And another outspoken reformist MP, Mohsen Armin, said the lifting of the sanctions "have nothing to do with the earthquake."

"We have always said we are waiting for a positive step from the White House, and the American leadership has given the signs. This should be seen as a good first step," he said.

TERRA.WIRE