Iran can make a large-scale prisoner swap immediately and is willing to hold direct talks with the US if it makes a major goodwill gesture such as releasing $8bn (£5.9bn) worth of Iranian assets locked abroad, Iran’s top diplomat has said. Iran’s foreign minister, Hossein Amir-Abdollahian, also said the US and Iran had “never been so close to reaching a deal as we are today”, referring to an agreement to revive the 2015 nuclear deal from which the US had walked out on in 2018. Iran and European powers have been staging talks on reviving the deal since February, but all sides now agree a conclusion has to be reached. The minister speaking at the Munich Security Conference on Saturday said Iran still needed to see flexibility by the US in providing political, legal and economic guarantees that the US will honour the nuclear deal. Asked about the possibility of prisoner swaps as part of the deal, he said “it is a completely humanitarian issue. There was a kind of agreement that was formed last year that all the prisoners at once will be exchanged”. He said the Americans are interested in linking the prisoners to the Vienna talks, but he said “from Iran’s point of view there is no relationship between the prisoners and the Vienna talks. Away from it, we can do it immediately.” With both sides normally remaining tight-lipped about the final stages of the negotiations, the minister’s remarks lift the lid on some of the remaining stumbling blocks. It also confirms the Americans are trying to include guarantees about the release of dual national political prisoners in the deal. He said the most important guarantee about the future status of any non-proliferation agreement was economic, and Iran had proposed that no sanctions could be applied legally to any deal struck between an Iranian company and a foreign company so protecting that deal from the threat of sanctions being slapped on them if the US pulled out of the deal again. He revealed the US chief Iran negotiator Rob Malley in a non-paper had suggested statements made by the US president, Joe Biden, at the G7 Summit in Cornwall in June that his administration would abide by the agreement were politically sufficient. But Iran’s envoy said this proposal was not enough due to the high wall of mistrust between the countries caused by the US ruining the previous deal by walking out. He proposed the parliaments of the countries signing the deal “could confirm some kind of support for the talks’ outcome”, suggesting this could be “at any reasonable or acceptable level”. He said the most important guarantee was economic, pointing out that Malley had told Iran via intermediaries that he cannot guarantee that the next administration will remain loyal to the commitment Biden had made. He claimed this stance conflicted with international law that requires governments to abide by the international agreements made by their previous government”. He also confirmed the US repeatedly through intermediaries had been seeking to persuade Iran to hold direct talks with the US. He said the US could present a big goodwill initiative to lift sanctions or release $10bn Iranian assets frozen in foreign banks. “Saying we have goodwill in words is not enough for direct talks. On the ground they have to show it in practice.”