"We will keep working with even greater urgency to bring back on track a key deal for non-proliferation and regional stability," Mora said.
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 refuses to hold direct talks with its arch-foe, the United States, resulting in the "proximity" talks arrangement involving Mora.
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.
The nuclear pact seemed near revival in March but 11 months of talks between Tehran and major powers in Vienna were thrown into disarray chiefly over Tehran's insistence that Washington remove the Islamic Revolutionary Guards Corps (IRGC), its elite security force, from the U.S. Foreign Terrorist Organizations (FTO) list.
Iran's Tasnim news agency, affiliated with the IRGC, blamed President Joe Biden administration's "weakness and its inability to make a final decision" for lack of progress in the talks.
"What prevented these negotiations from coming to fruition is the U.S. insistence on its proposed draft text in Vienna that excludes any guarantees for Iran's economic benefit," Tasnim said.
"Washington seeks to revive the deal to put restrictions on Iran without allowing Tehran to gain any economic benefit."
Under the nuclear pact, Tehran limited its uranium enrichment programme, a potential pathway to nuclear weapons though Iran says it seeks only civilian atomic energy, in exchange for relief from the economic sanctions.
But in 2018, then-U.S. President Donald Trump abandoned the deal, calling it too soft on Iran, and reimposed harsh U.S. sanctions, spurring Tehran to breach nuclear limits in the pact.
(Writing by Parisa HafeziEditing by Gareth Jones and Lisa Shumaker)
By Parisa Hafezi
