Iran's security chief Mohsen Rezaei on Tuesday told the visiting Pakistani army chief Asim Munir that Tehran would not allow nuclear material to leave the country, according to state TV.
"Not even a tiny bit of enriched nuclear material will leave Iran; such materials constitute a major asset and national wealth for the Iranian people, intended for use within the country," said Rezaei, Iran's secretary of the Supreme National Security Council.
"There will be no negotiations until America takes steps to build trust -- a process that must begin with the fulfilment of Iran's conditions," he added.
Iranian President Masoud Pezeshkian also rejected the idea of negotiations under US threats during his meeting with Munir, who is in Tehran as part of a renewed push to mediate a peace deal between the Islamic republic and the United States.
"The Americans must first remove the threats and sanctions; only then can we engage in dialogue," he said.
"Today, our nation does not trust America. It believes that if we enter the negotiations, they (the Americans) will attack us again."
Iran's chief negotiator and parliament speaker Mohammad Bagher Ghalibaf made similar remarks to Munir.
"We have nothing new to say; America cannot gain Iran's trust unless it fulfils the seven conditions," said Ghalibaf, noting that "threats and military manoeuvres cannot influence Iran's strategic decisions".
Iran has demanded, among other things, a ceasefire across the Middle East, the unfreezing of its assets abroad and the lifting of sanctions on its oil sector.
The Middle East war was sparked in late February by the United States and Israel when they launched a wave of surprise attacks on Iran, while Washington and Tehran were in the midst of negotiations on Iran's nuclear programme.
The warring parties agreed a memorandum of understanding in June that was expected to create a framework for a permanent resolution to the conflict, but the deal did not last long.
Negotiations have effectively been at an impasse since then, and recent indirect talks between the US and Iran on the sidelines of the UN General Assembly failed to produce a breakthrough.
Tehran had previously maintained it would not hand over its nuclear materials -- enriched to 60 percent, close to the atomic bomb threshold of 90 percent -- to any country but had hinted at the possibility of diluting them within Iran's borders.
Washington and its allies have imposed waves of sanctions on Iran, accusing it of seeking to build nuclear weapons, a charge Tehran has long denied.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)