State Department spokesperson Ned Price said in a statement the US believes it is still possible to "quickly reach and implement an understanding on return to mutual full compliance" with the 2015 Joint Comprehensive Plan of Action (JCPOA) as only a small number of outstanding issues remain to be settled from the last round of talks in June.
The seventh round, which is expected to begin early next month, will be the first since Iranian President Ebrahim Raisi took office in August. A conservative, Raisi has criticized his predecessor, Hassan Rouhani, for being too eager to reach a settlement with the Western powers and has ordered a comprehensive review of all aspects of the negotiation process begun in April.
"The new administration is trying to find out what are the shortcomings, what are the characteristics for the previous talks," Iranian Foreign Ministry spokesperson Saeed Khatibzadeh told France 24 earlier this month.
The deal initially reached in 2015 between Iran, the US, UK, France, Germany, European Union, Russia and China, and saw Iran accept strict limits on the purity of uranium-235 it could refine and volume it could store in exchange for the removal of sanctions against the Iranian economy. However, in 2018 then-US President Donald Trump unilaterally withdrew from the agreement and accused Iran of secretly violating the deal, reimposing sanctions afterward that crippled Iran's economy and exacerbated the effects of the COVID-19 pandemic.
In response, Iran began reducing its commitments to the deal, producing steadily higher purities of u-235 and storing greater quantities of the radioactive material, which can in some very high purities be used to make a nuclear weapon, but which is generally used to fuel nuclear power plants or conduct medical research. Highly enriched uranium can also be used to produce plutonium-239, the most common explosive in a nuclear weapon.
Iran has denied accusations that it is pursuing a nuclear weapon and Ayatollah Ali Khamenei, Iran's Supreme Leader, has issued a fatwa banning the use of all weapons of mass destruction. Israeli intelligence has also dismissed reports Iran might be close to a nuclear weapon, noting there were no indications of new weapons-level work alongside the new refinement efforts.
Nonetheless, the US and Israel have continued to posture as if time is running out. Last week, the Israeli government approved a special budget of $1.5 billion to draw up and rehearse plans for a potential attack on Iran's nuclear facilities, which are heavily guarded and many of which lay deep underground.
America and many of its regional allies, including Israel and Saudi Arabia, have said they want an even stricter version of the JCPOA than that created in 2015. Price said last week the US was not "optimistic, not pessimistic," but simply "clear-eyed" about the Vienna talks.