The European Union and United States said on Tuesday they were studying Iran's response to what the EU has called its "final" proposal to save a 2015 nuclear deal after Tehran called on Washington to show flexibility.
A US State Department spokesperson said the United States was sharing its views on Iran's response with the European Union after receiving Tehran's comments from the bloc.
"For the moment, we are studying it and we are consulting with the other JCPOA participants and the US on the way forward," an EU spokesperson told reporters in Brussels, referring to the nuclear deal by the official abbreviation JCPOA.
She declined to give a time frame for any reaction from the EU.
After 16 months of fitful, indirect US-Iranian talks, with the EU shuttling between the parties, a senior EU official said on Aug. 8 the bloc had laid down a "final" offer and expected a response within a "very, very few weeks".
Iran responded to the proposal late on Monday but none of the parties provided any details.
Earlier on Monday, Iran's foreign minister called on the US to show flexibility to resolve three remaining issues, suggesting Tehran's response would not be a final acceptance or rejection.
Washington has said it is ready to quickly seal a deal to restore the 2015 accord on the basis of the EU proposals.
Diplomats and officials have told Reuters that whether or not Tehran and Washington accept the EU's "final" offer, neither is likely to declare the pact dead because keeping it alive serves both sides' interests.
The stakes are high, since failure in the nuclear negotiations would carry the risk of a fresh regional war, with Israel threatening military action against Iran if diplomacy fails to prevent Tehran from developing a nuclear weapons capability.
Iran, which has long denied having such ambitions, has warned of a "crushing" response to any Israeli attack.
In 2018, then-President Donald Trump reneged on the nuclear deal reached before he took office, calling it too soft on Iran, and reimposed harsh US sanctions, spurring Tehran to begin breaching its limits on uranium enrichment.
