Foreign Minister Abbas Araghchi said Tuesday that Iran's right to enrich uranium on its soil was a "red line" after the United States submitted its proposal for a new nuclear deal.
"Continuing enrichment on Iranian soil is our red line," Araghchi said while on a visit to Lebanon, adding that his country will respond to the proposal in the coming days based on Iran's "principled positions and the interests of the Iranian people".
US President Donald Trump on Monday reiterated that Iran will not be allowed any enrichment of uranium under a potential deal with Washington.
Araghchi said the US proposal, submitted through mediator Oman, has "many ambiguities and questions".
On Saturday, Iran said it received "elements" of a US proposal for a nuclear deal following five rounds of talks that started in April and were mediated by Oman.
Uranium enrichment has remained a key point of contention between Washington and Tehran in the talks to seal a nuclear deal, with Iran defending what it says is its right to pursue a peaceful nuclear energy program and the US calling it a "red line".
"We will not ask anyone for permission to continue enriching uranium in Iran. However, we are ready to take steps... to ensure that this enrichment will not lead to the production of nuclear weapons," Araghchi said.
Araghchi was visiting Beirut following a stop in Cairo on Monday, where he met with Rafael Grossi, the head of the International Atomic Energy Agency (IAEA).
Grossi on Monday called for more transparency from Iran following a leaked report that showed Tehran had increased production of highly enriched uranium.
The IAEA report showed that Iran has ramped up production of uranium enriched up to 60 percent purity -- close to the roughly 90 percent level needed for atomic weapons.
Western countries, including the United States, have long accused Iran of seeking to acquire nuclear weapons, while Iran insists its nuclear program is for peaceful purposes.