Iran and the United States are set to resume their third round of nuclear negotiations, even as a hardening US military posture in the Middle East and lingering core divisions over the framework of a nuclear deal cast doubts over the fragility of the process and the looming risk of confrontation.

Omani Foreign Minister Sayyid Badr bin Hamad bin Hamood Albusaidi confirmed the development on Sunday night, expressing his pleasure at the progress and noting a "positive push to go the extra mile to finalize the deal". Oman, a mediator between the two nations, had previously hosted indirect talks on Iran's nuclear program and facilitated the latest round in Geneva last week.

Minutes after the confirmation, Iranian President Masoud Pezeshkian voiced cautious optimism in a post on social media, saying recent negotiations had "yielded encouraging signals", while emphasizing Tehran's readiness to confront "any potential scenario".

In a CBS News interview broadcast on Sunday, Iran's Foreign Minister Seyed Abbas Araghchi said he may meet with US President Donald Trump's special envoy Steve Witkoff on Thursday in Geneva, noting that a diplomatic solution remains possible.

'Peaceful program'

He said the deal should include Iran's "peaceful nuclear program" as well as lifting US sanctions against Iran, reaffirming Tehran's resolve to secure its right to uranium enrichment under the national nuclear program. He also stressed that Tehran has the right to self-defense if the US attacks Iran. "We have to hit, you know, the American base in the region."

Araghchi said Iran and the US can reach a nuclear deal better than the 2015 accord signed between Tehran and world powers. "This time, there is no need for that many details. We can agree on core principles and ensure that Iran's nuclear program is peaceful and will remain peaceful forever."

Talks were deadlocked for years after Trump's 2018 decision to unilaterally withdraw the US from the landmark 2015 Joint Comprehensive Plan of Action. Indirect talks last year failed to produce an agreement, mainly due to disputes over a US demand that Iran abandon uranium enrichment on its soil — a step Washington views as a pathway to a nuclear bomb. Iran has repeatedly denied seeking such weapons.

The US administration has been pushing for concessions from its longtime adversary and has built up the largest US military presence in the Middle East in decades. The US has deployed two aircraft carriers to the region in recent weeks, along with additional warplanes and naval vessels.

Meanwhile, Witkoff said on Saturday that the US president wonders why Iran has not yet "capitulated" and agreed to curb its nuclear program.

"I don't want to use the word 'frustrated', because he understands he has plenty of alternatives, but he's curious as to why they haven't … I don't want to use the word 'capitulated', but why they haven't capitulated," Witkoff said during an interview with Fox News' My View with Lara Trump.

In response, Araghchi wrote on social media: "Curious why we don't capitulate? Because we are Iranian."

A senior Iranian official told Reuters that significant gaps remain between the two sides.

"Both sides must agree on a realistic timetable for lifting sanctions," the official said.

Washington has insisted that any deal with Iran must also include limits on long-range missiles and a rollback of alleged support for regional militia groups. But analysts say such conditions would be extremely difficult for Iran to accept, as they would undermine its national security interests.

cuihaipei@chinadaily.com.cn