Mahmoud Ahmadinejad told a UN news conference in New York that talks with the European Union on Iran's nuclear programme were on the right track.
In the most explicit indication by the Iranian leader that Tehran is seriously considering complying with the main condition for broader talks on the issue, he said: "We have said that under fair conditions and just conditions we will negotiate about it."
In an apparent reference to the US, he said: "We believe those negotiations are moving on the right path. Hopefully others will not disrupt the work."
Repeatedly questioned about the programme that Washington and its allies say hides efforts to build a nuclear weapon, Ahmadinejad said: "The bottom line is, we do not need a bomb, not like what others think."
He later added: "We are not seeking a nuclear bomb, let me make that clear."
The Iranian leader spoke during his three-day visit to New York to address the UN General Assembly, where he also defended his country's uranium enrichment and attacked US policy.
Iran ignored a UN Security Council demand that it should suspend uranium enrichment by August 31.
According to diplomats, the US and its European allies have decided to give Iran until early October to make progress in nuclear talks before they start discussing UN sanctions against Tehran.
Britain, France and Germany drew up a package of economic and political incentives, hoping to persuade Iran to give up uranium enrichment.
But Iran has not given a firm response.
Margaret Beckett, the British foreign secretary, said on Wednesday: "What we are looking for is a clear and concrete signal that Iran wishes to negotiate.
"If things drag on as they have been, then there are concerns and consequences about how that can continue."
Regarding the documents and access to nuclear facilities that Iran has already given the International Atomic Energy Agency, Ahmadinejad said: "I am at a loss in understanding what else we need to do to provide guarantees."