Biden, who takes office on January 20, has said he would rejoin the accord if Tehran first resumed strict compliance, and would work with allies "to strengthen and extend it, while more effectively pushing back against Iran's other destabilising activities".
Under Trump, tensions between the USA and Iran have escalated, pushing the two sides to the brink of war earlier this year.
Trump unilaterally withdrew the U.S. from that pact in May 2018 and launched a "maximum pressure" campaign against Iran with sanctions that plunged its economy into a deep recession. Trump has since piled punishing sanctions on Iran that have devastated the country's economy and crashed its currency.
Iranian President Hassan Rouhani's hopes are Wednesday pinned on a change in policy towards the Islamic Republic by US President-Elect Joe Biden.
Other signatories to the Iran nuclear deal expressed opposition to President Trump's Iran policy and the endangering of the deal which they have tried to keep on life support. Iran's enriched uranium stockpile, which would have been under 300 kilograms (660 pounds) in the deal, now stands at over 2,440 kilograms (5,380 pounds), according to the latest report by United Nations inspectors.
"We are confident that a constructive approach by the USA toward the Vienna nuclear agreement could contribute significantly to breaking the current negative spiral we are seeing with Iran, and opening new prospects for the preservation of the JCPOA", Sasse said. Iran long has maintained its nuclear program is for peaceful purposes.
At the same time, Iranian Foreign Minister Javad Zarif did not rule out the possibility of a dialogue on Iran's return to the nuclear agreement.
"With the new U.S. administration taking office next year, we will get the opportunity to again use the JCPOA (the nuclear deal with Iran) for what it was meant for - to curtail Iran's nuclear programme", a German diplomat said, speaking on condition of anonymity.
