Iran's top negotiator at nuclear talks underway in Vienna said that the discussions were on the right track and consultations would continue.
Deputy Foreign Minister Abbas Araghchi told Iranian media that "good discussions" had been held among the delegations from Britain, France, Russia, China and Germany.
"It seems that a new understanding is emerging and there is now common ground ... on the final goal," Araghchi was quoted as saying by state television.
According to Araghchi, Iran has drafted a roadmap to serve as the basis on which the Islamic Republic could return to its technical commitments in the nuclear deal while the US lifts sanctions.
Araghchi cautioned that there remain "serious disagreements," but said that technical consultations would go on in the coming days.
The negotiators have been meeting in working groups in the Austrian capital for more than a week.
The goal is to revive the 2015 nuclear deal that was crafted to constrain Iran's nuclear programme. It has been hanging by a thread since 2018, when then-president Donald Trump pulled the US out of the accord and Tehran began to increasingly violate its terms.
Iran announced a major hike in its uranium enrichment programme this week, igniting fresh fears over the ability of the country to produce nuclear weapons.
Later on Saturday, the International Atomic Energy Agency confirmed that Iran had enriched uranium to 60 per cent, after an inspection of the facility at Natanz where the production process had begun.
Iran enriched its uranium up to 60 per cent for the first time on Friday night, according to Ali Akbar Salehi, the head of the Iran Atomic Energy Organization (AEOI).
The exact level of enrichment is still being analyzed, an IAEA spokesperson said in Vienna.
In Vienna, the US has a team present but is not engaging in direct talks with their Iranian counterparts. Instead, other delegations serve as intermediaries.
Russian diplomat Mikhail Ulyanov tweeted on Saturday that the latest high-level round of talks had ended with participants showing "determination to continue negotiations with a view to complete the process successfully as soon as possible."
He said the progress made so far had been "noted" but, like Araghchi, did not provide details.
Negotiators are trying to get both Iran and the US to fully recommit to the deal, which would mean Iran coming back into compliance and Washington easing sanctions that have crippled Iran's economy.