VIENNA: Negotiators trying to save the Iran nuclear deal meet on Sunday to take stock at the end of the latest round of talks, and a day after the presidential election in the Islamic republic.

The meeting is part of their regular discussions since early April, aimed at bringing the US back to the 2015 landmark agreement and Iran back into compliance with curbs on its nuclear programme in exchange for sanctions relief.

But it comes a day after Ebrahim Raisi was declared the winner of Iran's presidential election.

Negotiators have said the presidential election is not expected to influence the talks though Raisi's views are widely seen as a break from the more moderate stances of former president Hassan Rouhani.

Iran's envoy, Deputy Foreign Minister Abbas Araghchi, said that after Sunday's meeting in Vienna negotiators would take a break to return to their capitals, ending the sixth round of talks.

"We are now closer to an agreement than ever. But it is not an easy task to close the distance currently between us and an agreement," he told Iran's national television.

"At this point, it is clear which fields, which actions are possible and which are not. Therefore, it is time for all sides, especially our counterparts, to be able to make their final decision."

He added he could not say how many days the latest break would last.

Mikhail Ulyanov, the Russian envoy at the EU-chaired talks, said Sunday's meeting would "decide on the way ahead".

"An agreement on restoration of the nuclear deal is within reach but is not finalised yet," he wrote on Twitter on Saturday.

Parties to the agreement -- Britain, China, Germany, France, Russia and Iran -- have been meeting in Vienna with indirect US participation to restore the deal, which promised Tehran sanctions relief in exchange for curtailing its nuclear programme.

The deal was thrown into disarray in 2018 when former US president Donald Trump withdrew and reimposed sanctions, leading Iran in turn to step up its nuclear activities from 2019 onwards.