Speaking to CBS News on Sunday, Iran's Foreign Minister Abbas Araghchi said details of a possible deal were being drawn up ahead of the renewed talks on Tehran's nuclear programme, after Washington's envoy Steve Witkoff had publicly wondered why Tehran had not yet "capitulated".

Badr Albusaidi, foreign minister of regional mediator Oman, said talks would resume on Thursday in Geneva "with a positive push to go the extra mile towards finalising the deal".

US threats of military action have multiplied since a nationwide protest movement in Iran sparked a crackdown that rights groups say killed thousands. On Sunday, Iranian students held competing pro- and anti-government protests, with critics of the clerical leadership risking arrest or worse if they are caught.

"If the US attacks us, then we have every right to defend ourselves," Araghchi said, alluding to American interests in the region as potential targets.

Still, he said, "there is a good chance to have a diplomatic solution".

In a social media post, Iran's President Masoud Pezeshkian likewise said previous talks "yielded encouraging signals".

After a recent round of discussions in Geneva, Iran said it was preparing a draft proposal for an agreement that would avert military action.

"I believe that when we meet, probably this Thursday in Geneva again, we can work on those elements and prepare a good text and come to a fast deal," Araghchi told CBS.

Axios had earlier reported, citing an unnamed senior US official, that if Iran submitted its proposal in the next 48 hours, Washington was ready to meet again later in the week "to start detailed negotiations".

The US has sent two aircraft carriers to the Middle East in recent weeks, along with other jets and ships, and has also shored up its air defences in the region to back up its threats of military intervention.

US President Donald Trump's chief Middle East negotiator Witkoff said in a Fox News interview broadcast Saturday that the president was questioning why Iran had not yet given in to the pressure.

"He's curious as to why they haven't... I don't want to use the word 'capitulated', but why they haven't capitulated," he said.

"Why haven't they come to us and said, 'We profess we don't want a weapon, so here's what we're prepared to do'?"

Western governments fear Iran's nuclear programme is aimed at developing a bomb, which Tehran has long denied, though it insists on its right to enrich uranium for civilian purposes.

On the subject of uranium enrichment, Araghchi said Sunday that Iran had "every right to decide for ourselves".

- Fears of war -

A previous round of diplomacy last year was interrupted by Israel's bombing campaign against the Islamic republic.

That sparked a 12-day conflict in June that the US briefly joined with strikes on Iran's nuclear facilities.

Despite the recent Oman-mediated talks, Iranians' fears of a new conflict have grown.

"I don't sleep well at night even while taking pills," Tehran resident Hamid told AFP.

IT technician Mina Ahmadvand, 46, believes that "at this stage, war between Iran and the US as well as Israel is inevitable".

"I don't want war to happen, but one should not fool around with the realities on the ground."

The concerns have prompted several foreign countries to urge their citizens to leave Iran, including Sweden, Serbia, Poland and Australia.

- Protests -

Iran has previously said that quickly striking a deal is in its interests if it means relief from sanctions that have hamstrung its economy, which contributed to protests late last year over the high cost of living.

Those demonstrations quickly expanded into mass anti-government protests that marked one of the largest challenges to the Islamic republic's leadership in years, prompting a deadly crackdown by authorities that saw thousands killed, according to rights groups.

On Sunday, Iranian students gathered for fresh pro- and anti-government rallies commemorating those killed following similar gatherings the day before.

Local and diaspora media outlets reported demonstrations at multiple Tehran universities, with some participants waving the flag of Iran's deposed monarchy, and others chanting "death to the shah", who was toppled by the 1979 Islamic revolution.

Trump had initially cheered on the protesters, threatening to intervene on their behalf amid the crackdown, but his threats soon shifted to Iran's nuclear programme.

Voicing their support for the protests, several Iraq-based Kurdish-Iranian groups announced on Sunday that they were forming a political coalition to unite against Iran's Islamic system.

The main goals of the alliance, a joint statement said, are "the struggle to overthrow the Islamic republic of Iran, and to achieve self-determination for the Kurds".