US said it will respond to the European Union's "final" text on reviving the deal in private without giving a timeline.
The only way to revive the 2015 Iran nuclear deal is for Tehran to abandon its extraneous demands, the US State Department said, saying Washington believes everything that can be negotiated already has been.
State Department spokesman Ned Price told a briefing on Monday that the United States would provide its response to the European Union's "final" text on reviving the deal in private but gave no timeline.
"The only way to achieve a mutual return to compliance with the JCPOA is for Iran to drop further unacceptable demands that go beyond the scope of the JCPOA. We have long called these demands extraneous," Price said.
The EU asked for a response on Monday, diplomats said, and Iran has said it will comply.
US President Joe Biden's administration has been trying to resurrect the 2015 agreement, named the Joint Comprehensive Plan of Action (JCPOA), which was abandoned by Biden's predecessor Donald Trump in 2018.
Under the deal, Tehran limited its nuclear program in exchange for relief from US, EU and UN sanctions.
'Relative progress made'
The IAEA's board of governors adopted a resolution in June, censuring Iran for failing to adequately explain the discovery of traces of enriched uranium at three previously undeclared sites.
The Iranian foreign ministry official added on Monday that, during the talks of the past few days, "we shared our positions with the other sides, and relative progress was made in some issues."
He added that the negotiating team looks to "protecting the rights and interests of the Iranian nation" as well as "ensuring the benefits and guaranteeing the sustainable implementation of the other party's obligations and preventing the repetition of US illegal behaviour".
The negotiations to revive the deal began in April 2021 before coming to a standstill in March.