
Iransaid Monday it willonlyreturntoViennain order tofinalisean agreement to revive its landmark 2015nucleardealwith world powers, with the last steps dependent on Washington.
Tehran has been engaged in long-running negotiations in the Austrian capital to revive thedeal, known formally as the Joint Comprehensive Plan of Action (JCPOA), with Britain, China, France, Germany and Russia directly, and the United States indirectly.
"We will not be going toViennafor new negotiations but tofinalisethenuclearagreement," foreign ministry spokesman Saeed Khatibzadeh told reporters in Tehran.
However,Iransaid there were still outstanding issues that it was waiting on Washington to settle.
"At the moment, we do not yet have a definitive answer from Washington," Khatibzadeh said.
"If Washington answers the outstanding questions, we can go toViennaas soon as possible."
The JCPOA gaveIransanctions relief in exchange for curbs on itsnuclearprogramme to guarantee that Tehran could not develop or acquire an atomic bomb -- something it has always denied wanting to do.
But the US unilateral withdrawal from the accord in 2018 under then-president Donald Trump, who reimposed biting economic sanctions which promptedIranto begin rolling back its own commitments.
'Final phase'
TheViennatalks aim toreturnthe US to thenucleardeal, including through the lifting of sanctions onIran, and to ensure Tehran's full compliance with its commitments.
Iranian and US delegations inViennado not communicate directly but through other participants and the European Union, the talks' coordinator.
Nearly a year of negotiations have brought the parties close to renewing the 2015 accord.
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But the talks were halted last month, after Russia demanded guarantees that Western sanctions imposed following its invasion of Ukraine would not damage its trade withIran.
Russian Foreign Minister Sergei Lavrov later said Moscow had received the necessary guarantees from Washington on trade withIran.
Among the key sticking points is Tehran's demand to remove from the US terror list the Islamic Revolutionary Guard Corps, the ideological arm ofIran's military.
Washington recently confirmed that sanctions on the Guards would stay.
On Wednesday, the US Treasury announced measures targeting several entities it accused of involvement in procuring supplies forIran's ballistic missile programme.
A day later, Khatibzadeh said Washington's imposition of the fresh sanctions on the Islamic Republic showed its "ill will" towardsIran.
On Monday, Khatibzadeh levelled further criticism at the US.
"Today, in the final phase, the United States seeks to depriveIranof the economic benefits of the agreement," Khatibzadeh said.
On Sunday, however,Iran's Foreign Minister Hossein Amir-Abdollahian said an agreement was "close", during a phone conversation with UN Secretary-General Antonio Guterres.
"We have passed on our proposals on the remaining issues to the American side through the EU senior negotiator, and now the ball is in US court,"Iran's top diplomat said.