Iranian President Hassan Rowhani said in an interview due to air Wednesday that his administration will not develop nuclear weapons, dpa reported.
In an interview with NBC News, Rowhani also offered assurances that he has full authority to make a deal with the West on the country's nuclear programme.
Rowhani is to address the UN General Assembly in New York on Tuesday for the first time as president. His predecessor Mahmoud Ahmadinejad was known for his firey anti-American speeches at the annual gathering.
Rowhani offered last week to hold nuclear talks with international powers as early as this month during the annual UN General Assembly, the Iranian news agency ISNA reported.
Since taking office last month, Rowhani has transferred responsibility for Iran's long-running nuclear talks with the 5+1 group - UN Security Council veto powers Britain, China, France, Russia and the United States, plus Germany - to the Iranian Foreign Ministry.
His newly appointed foreign minister, Mohammad Javad Zarif, has already agreed to meet on September 22 in New York - on the General Assembly sidelines - with EU foreign policy chief Catherine Ashton to discuss a return to the stalled P5+1 talks. Western powers accuse Iran of pursuing nuclear weapons capability, which Tehran denies.
There are however no plans for Rowhani to meet with US President Barack Obama on the sidelines, the White House said Wednesday.
Spokesman Jay Carney however stressed that Obama believes there is room for a diplomatic solution on Iran's nuclear programme.
"We have heard a lot in the world from President Rowhani's administration about its desire to improve the government of the Islamic Republic of Iran's relations with the international community," Carney said. "And President Obama believes we should test that assertion, and we are and we will do that."
Rowhani and Obama exchanged letters, which Rowhani described as positive and constructive.
"It could be subtle and tiny steps for a very important future. I I believe the leaders in all countries could think in their national interest and they should not be under the influence of pressure groups," he told NBC through a translator. "I hope to witness such an atmosphere in the future."
The US letter said "the US is ready to resolve the nuclear issue in a way that allows Iran to demonstrate that its nuclear programme is for exclusively peaceful purposes," spokesman Jay Carney revealed Wednesday.
It also said there was a need to act urgently because the window of opportunity for a diplomatic solution "will not remain open indefinitely."