Iran has rejected the notion, floated in Politico on Monday, that it should make specified restrictions in its nuclear program in return for limited relief from United States sanctions. The US publication claimed that President Joe Biden was planning to make the proposal to help rescue Iran’s 2015 nuclear agreement with world powers.

"No proposal is needed for the US to rejoin the JCPOA," the Iranian Permanent Mission to the UN said in a tweet on Monday. "It only requires a political decision by the US to fully and immediately implement all of its obligations under the accord and abide by UNSCR 2231."

United Nations Security Council Resolution 2231 was passed in 2015, with the support of the US, endorsing the 2015 nuclear deal, known as the JCPOA, the Joint Comprehensive Plan of Action. President Donald Trump withdrew the US from the JCPOA in 2018 and imposed stringent sanctions on Iran, which in 2019 began expanding its atomic program beyond JCPOA limits.

Iran's state-run international channel, Press TV, on Monday quoted a senior official that Iran was "in touch" with the remaining JCPOA signatories – Germany, France, the UK, Russia and China. “Twenty precent uranium enrichment is in line with Paragraph 36 of the JCPOA and will be stopped only if the US lifts all the sanctions," the official said. "The Biden administration is losing time, and if it fails to lift the sanctions soon, Iran will take the next steps, which will be further reduction of its JCPOA commitments."

According to Politico, with a view to June’s Iranian presidential elections, the Biden administration officials plan to present their proposal this week. Two sources "familiar with the situation" told Politico that the US would ask Iran to halt some nuclear activities, including work on advanced centrifuges and enrichment uranium to 20 percent purity, in exchange for some relief from US economic sanctions: details were reportedly still being worked on.

“We have also been open that we are talking with our [international] partners … about the best way to achieve this, including through a series of initial, mutual steps,” a senior Biden administration official told Politico. "We have been looking at options for doing so, including with indirect conversations through our European partners.”

During the election Biden pledged to renew the JCPOA but so far has continued sanctions introduced by Trump as ‘maximum pressure’ that he said would force Iran to accept US demands including ending all enrichment, scrapping missile defense and breaking links with regional allies, including Palestinian groups.

Iran’s presidential election – with a new president replacing outgoing President Hassan Rouhani in early August – is not the only timetable. A three-month "window of opportunity for diplomacy" provided by the access agreement between Iran and the International Atomic Energy Agency (IAEA) is due to end in May. Iran has said it will destroy footage from all IAEA cameras at the end of the three months if US sanctions are not lifted. With Iran is no longer implementing its Additional Protocol to the Nuclear Non-Proliferation Treaty, the expiry of the agreement, reached by IAEA chief Rafael Mariano Grossi in Tehran in February, would reduce agency access to that required by the NPT.

Iran's thirteenth Presidential election to choose a successor to Rouhani is due on June 18. Most potential candidates favored by the public or political groups − including Foreign Minister Mohammad Javad Zarif who himself denies being a contender – not confirmed they will run. Five-day registration begins on May 11, and candidates often declare late.