(Bloomberg) -- Iranian negotiators at nuclear talks with world powers presented draft proposals for how to overcome the biggest hurdles to reviving their 2015 nuclear accord, texts that will help determine whether the sides see the basis for a deal. 

Ali Bagheri Kani, Iran’s chief nuclear negotiator, said the documents address the removal of U.S. sanctions and how Iran intends to roll back advances in its atomic activities, the semi-official Tasnim news agency reported. The drafts were submitted to European diplomats on Wednesday night, it said.

Mediators from three European nations and other signatories to the landmark agreement will scrutinize the proposals for evidence Tehran is prepared to build on wording agreed during six previous rounds of talks rather than wanting to re-negotiate. 

The current talks in Vienna are the first since the election in June of Iran’s President Ebrahim Raisi, with U.S. officials pessimistic of reaching an agreement with his hardline administration.

Disagreements over the sequencing of U.S. sanctions removal and how Tehran scales back a significant expansion of its nuclear program emerged as major sticking points in the talks, which were stalled for five months before they restarted in the Austrian capital on Monday.  

Oil traders are watching closely. Restoring the landmark deal that the Trump administration abandoned in 2018 would enable OPEC-member Iran to rapidly increase oil exports and re-enter a market that’s been tightly supplied since pandemic lockdowns began to ease. 

As the diplomacy grinds on, developments in Iran are raising the stakes.

On Wednesday, the International Atomic Energy Agency, which has been seeking access to a site on the outskirts of Tehran that’s involved in the production of centrifuges, said the Islamic Republic had escalated its atomic work by feeding a line of advanced centrifuges to produce uranium enriched to 20% purity at its plant in Fordow.

Bagheri Kani is due to meet IAEA Director General Rafael Mariano Grossi on Thursday.

European diplomats are keen to secure some form of early breakthrough to ease a standoff that destabilized the Persian Gulf and could weaken post-Cold War efforts to limit nuclear proliferation. 

So far, Iran has had several meetings with the European Union addressing lifting sanctions and nuclear compliance. Those so-called “working groups” are also set to continue on Thursday, Tasnim said. Iran also wants the U.S. to rule out any future exit from the deal, but the Biden administration has said it can’t tie the hands of successor governments.    

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