Guterres, in a report to the UN Security Council, also appealed to “extend the waivers with regard to the trade-in oil with the Islamic Republic of Iran, and fully renew waivers for nuclear non-proliferation projects”.

The secretary general’s appeal to Washington came on the backdrop of pending discussions on the revival of the Joint Comprehensive Plan of Action (JCPOA), the deal under which Iran agreed to curbs on its nuclear programme against waiver of many foreign sanctions against it.

The 15-member council was scheduled to discuss the secretary-general’s biannual report on the implementation of a 2015 resolution that lays down the nuclear deal between Iran, the United States, the United Kingdom, France, Germany, China, Russia and the European Union.

In 2018, the then Donal Trump administration abandoned the deal and began imposing stricter sanctions, prompting Tehran to defy some of the nuclear limits in 2019, said an Al Jazeera report.

One such instance was the end of extra monitoring of its nuclear sites by the IAEA in February. The inspections ended last week after temporary extension of the deal twice.

Iran has said it will return to full compliance after the removal of US sanctions and the world powers must work on the revival of the deal.

According to an Al Jazeera report, spokesman Saeed Khatibzadeh said that during the Vienna talks, “it has been constantly stressed that the Islamic Republic of Iran is fully prepared to stop its remedial efforts and restart implementing its commitments under the JCPOA with the condition that it is fully implemented by the US”.

“I appeal to the United States to lift or waive its sanctions outlined in the plan,” said Guterres, while also appealing to Iran to return to full implementation of the deal, according to the report.

Iran has refined uranium up to a purity ofar above As per the deal, Iran can have refined uranium up to a purity of 3.67 per cent but it is roughly 60 per cent, much closer to the 90 per cent suitable for atom bomb cores, Al Jazeera reported.