Iran, reeling from international sanctions over its nuclear programme and facing four more years with Barack Obama as leader of arch-enemy the United States, does not rule out direct talks with Washington but says they will not come overnight.

Obama's re-election drew an ambiguous response from President Mahmoud Ahmadinejad, who dismissed the US elections as a "battleground for the capitalists," at a forum on democracy in Indonesia.

Without directly commenting on Obama's victory, he lambasted democracy in the West as having "turned into the rule of a minority over the majority."

But behind the flamboyant rhetoric, senior regime figures have expressed cautious signs of interest in the election of Obama, who four years ago famously "extended his hand" to Tehran and may be preparing to do so again.

An influential cleric among the ruling conservatives, judiciary chief Ayatollah Sadeq Larijani, did not rule out Tehran and Washington coming "to the negotiating table" one day but warned it would not happen "overnight."

Larijani said on Wednesday that "relations with the United States are not simple."

The United States, which Tehran dubs the "Great Satan," severed diplomatic relations with Iran after the 1979 takeover of the US embassy in Tehran, and the two have been in a tense stand-off ever since.

"Four years ago, Obama was elected on a platform for change and said he was extending his hand for cooperation with Iran, but he acted otherwise and unprecedented sanctions were imposed," Larijani said.

Obama has rallied US allies against Iran, toughening sanctions, with Tehran's oil exports and access to world financial systems being key targets.

The United States and other world powers, including Tehran's arch-enemy Israel, accuse Iran of using its nuclear programme to mask a drive for atomic weapons. Tehran denies that, saying it is for purely peaceful purposes.

The last offer called for Iran to cease enriching uranium to purities of 20 percent -- technically not far from the 90 percent needed for a nuclear weapon.

It also wanted Iran to close its Fordo enrichment facility and to export existing stockpiles of 20-percent purity uranium.

Iran rejected that, saying it did not offer sufficient relief from sanctions that have begun to cause real economic problems.

Larijani's brother and international affairs adviser, Mohammad Javad Larijani, reiterated that negotiating with Washington "is not taboo," but any decision to renew contact "is a prerogative of the supreme leader."

"If the interest of the regime requires it, we are prepared to negotiate with the Satan in the pits of hell," he said on Wednesday.

A Western ambassador in Tehran said the regime "gives the impression of being willing to be more realistic in its negotiations with major powers, providing they offer it an honourable way out of the crisis."

This could include, according to many Western diplomats in Iran, the revival of bilateral contact with the United States.

Another European ambassador said "both sides have shown some interest (in such a revival), but the question is what the Iranians are going to ask for, and if Washington is willing to give it."

In recent months, Washington has repeatedly expressed readiness for direct talks with Iran. Tehran has declined, saying its conditions were not met.

Foreign ministry spokesman Ramin Mehmanparast has said Iran "respects the vote of the American people."

But "the wall of mistrust can only be reduced if the US government respects the will and the rights of the Iranian people and changes its past mistaken policies."

The second European ambassador sees hope nonetheless.

"Whether it's nuclear talks or a possible resumption of dialogue with Washington, the Iranians are insisting on what they call the recognition of their rights as well as mutual respect," he said.

"The wording is vague enough to allow solutions if both parties are open to it," he added. "The re-election of Obama in any case opens a window of a few weeks or months to overcome the crisis."

As it stands, a new round of talks between Iran and six world powers, the first since June, is expected by the end of the year, or in early 2013, analysts say.

Mark Fitzpatrick, nuclear expert at the International Institute for Strategic Studies in London, said "it's pretty clear that the United States and its European allies are gearing up to try again for diplomatic engagement.

"But the question is, what will be on the table? Iran won't be making concessions unless it gets some form of sanctions relief," he said.

As put by Mark Hibbs, at the Carnegie Endowment for International Peace, "there is reason for some optimism, but it is guarded optimism because in the final analysis it depends on whether Iran will 'play.' If they won't, all bets are off."