Indirect talks between Tehran and Washington aimed at breaking an impasse over how to salvage Iran's 2015 nuclear pact have ended in Qatar without the progress "the EU team as coordinator had hoped-for", EU's envoy Enrique Mora tweeted on Wednesday.
"We will keep working with even greater urgency to bring back on track a key deal for non-proliferation and regional stability," Mora said.
A U.S. State Department spokesperson said in a statement that Iran "failed to respond positively to the EU's initiative and therefore ... no progress was made" in the talks.
The EU-mediated, indirect talks started on Tuesday with Mora as the coordinator, shuttling between Iran's Ali Bagheri Kani and Washington's special Iran envoy Rob Malley based in separate rooms in a hotel in Qatar's capital.
Iran's foreign ministry spokesman Naser Kanani said Bagheri Kani and Mora "will be in touch about continuing the path and the next stage of the talks", Iran's semi-official Tasnim news agency reported.