Iran says its nuclear programme is for energy generation
The Iranian president has said his country sees no need for nuclear weapons, while insisting Iran will not abandon its pursuit of nuclear energy.
In an interview with US network NBC Mahmoud Ahmadinejad did not explicitly rule out the possibility that Iran would acquire nuclear weapons.
He said simply that it was "not a part of our programmes and plans".
Meanwhile, Iranian security forces were on alert ahead of an annual rally expected to draw opposition leaders.
The opposition figures, who reject Mr Ahmadinejad's re-election in June, have called on their supporters to turn out in large numbers at the Quds, or Jerusalem, Day rally, which is being held in support of the Palestinian cause.
In his interview with NBC, the Iranian president said he did not "see any problems" with the elections.
Talks to resume
Speaking about Iran's nuclear programme, Mr Ahmadinejad said his country would not yield to pressure from the UN, the US and European states.
Western powers maintain Iran is covertly developing nuclear arms, a charge Iran denies.
They have called on Iran to suspend its programme of uranium enrichment, which Tehran says is entirely peaceful.
Mr Ahmadinejad is due to address the UN General Assembly next week, and Iran is due to hold fresh talks on its nuclear programme with world powers next month.
"If you are talking about the enrichment of uranium for peaceful purposes, this will never be closed down here in Iran," he told NBC.
Asked repeatedly whether there were any conditions under which Iran would develop a nuclear weapon, Mr Ahmadinejad each time replied that Iran had no use for such arms.
"We don't need nuclear weapons," he said.
"Without such weapons, we are very much able to defend ourselves."
Questioned about the disputed elections in June, the Iranian leader defended their legality.
Iran's election laws are built on "the strongest... foundations," the president said, and "the law prevails. I don't see any problems."
Mr Ahmadinejad claimed victory, but opposition supporters who claimed the vote was rigged staged mass protests.
Officials say at least 30 people were killed in the protests that ensued, while opposition groups put the figure at more than 70.
In the Iranian capital, Tehran, security forces were braced for Friday's rally.
Television pictures showed thousands of people marching in the city. Opposition supporters wearing green - Mr Mousavi's party colours - were taking part in the rally with pro-government supporters, AFP news agency reported.
Mr Ahmadinejad is due to give a speech at a university later.
Among the opposition leaders expected to appear at the rally were Mir Hossein Mousavi, who emerged as Mr Ahmadinejad's main challenger, and Mehdi Karroubi.
Iran's Revolutionary Guards Corps said it would deal "decisively" with any effort to stage an opposition protest.
Former BBC Tehran correspondent Jim Muir says opposition groups have not managed to hold a big rally for over two months and this is an opportunity, though one fraught with danger, for them to show they are still in contention.
It remains to be seen, he adds, whether security forces will take action against possible passive displays of defiance, such as the wearing of green, the colour adopted as the symbol of the reform movement led by Mr Mousavi.