"If the US is interested in ensuring that Iran will not have nuclear weapons, a deal is within reach, and we are ready for a serious conversation to achieve a solution that will forever ensure that outcome," Araghchi posted on X,
France 24 reports.
"Enrichment in Iran, however, will continue with or without a deal," he said.
Iran currently enriches uranium to 60 percent, far above the 3.67-percent limit set in the 2015 deal but below the 90 percent needed for a nuclear warhead.
Tehran says its nuclear ambitions are for civilian purposes only, and entirely peaceful.
It also insists its right to continue enriching uranium for peaceful purposes is "non-negotiable", but says it would be open to temporary restrictions on how much uranium it enriches and to what level.
On Wednesday, Iranian atomic energy agency chief Mohammad Eslami reiterated that Tehran "does not seek nuclear militarisation", and said enrichment was under the supervision of the UN nuclear watchdog.
"The dismantling of enrichment is not accepted by Iran," Eslami said.
Araghchi also said Sunday the country was ready to rebuild trust with European powers considering whether to reimpose UN sanctions on the Islamic republic under a 2015 nuclear deal.
"Iran is ready, should it observe genuine will and an independent approach from the European parties, to begin a new chapter in its relations with Europe," he told a diplomatic forum in Tehran.
"If Europe possesses the necessary will to rectify this path, Iran sees no obstacle to rebuilding mutual trust and expanding relations."
On Friday, senior Iranian diplomats met counterparts from Britain, France and Germany for talks on the status of US-Iran nuclear negotiations.
