There was a “renewed sense of purpose” at negotiations in Vienna to resurrect the Iran nuclear deal, the co-ordinator of the talks said, even as Tehran insisted it was not backing down from its previous positions.
Russia's envoy said the meeting “was rather short and constructive”, with commonalities on the need to finalise the talks and return to the deal swiftly.
EU diplomat Enrique Mora, the co-ordinator, said he felt there had been “a renewed sense of purpose in the need to work and to reach an agreement on bringing the” 2015 deal back to life.
But he said gaps remained, warning “we don't have all the time in the world".
“It's difficult, it's a very difficult endeavour. There are still different positions that we have to marry. And this is the gist of the negotiation and we will see how we can proceed, how we can advance,” Mr Mora added.
Tehran's top negotiator, Ali Bagheri Kani, said: “Iran underlined that it seriously continues the talks based on its previous position.
“Iran is serious about reaching an agreement if the ground is paved … the fact that all sides want the talks to continue shows that all parties want to narrow the gaps.”
Iran had been warned by the UK that this was its last chance to re-enter the nuclear deal it agreed with world powers, ahead of the talks resuming in Vienna.
“This is really the last chance for Iran to sign up and I strongly urge them to do that because we are determined to work with our allies to prevent Iran securing nuclear weapons,” said UK Foreign Secretary Liz Truss.
The UK is one of the signatories to the deal to which Iran agreed, as are China, the EU, France, Germany and Russia.
In 2018, former US president Donald Trump unilaterally withdrew from the pact and reintroduced heavy sanctions on Iran. Under the terms of the 2015 deal, those financial penalties had been removed in return for curbs on Tehran’s nuclear capacity.
Since the reimposition of the sanctions, Iran has responded by repeatedly breaching the limits set out in the deal.
After the most recent round of talks last week in Vienna, Iran was accused by the US and European powers of maximalist demands and seeking sweeping changes to draft agreements reached earlier this year.
US diplomats, led by special envoy Robert Malley, are indirectly involved and will join the talks at the weekend. Mr Trump's successor Joe Biden has said he wants to return to the deal.
Russia’s envoy to the negotiations, speaking before the talks resumed on Thursday, said that he was feeling optimistic while also saying “many differences remain”.
Mikhail Ulyanov said his delegation's contacts with the US and Iran “prove that both sides are very serious” about restoring the deal “but their visions of relevant ways and means differ".
“The task of the negotiators is to overcome these differences. It’s feasible in the light of unity of purpose.”
Separately, Ms Truss on Wednesday conceded that Britain owed a decades-old £400 million ($528.26m) debt to Tehran and insisted her government was working to “resolve the issue”.
The debt, related to a cancelled order for 1,500 Chieftain tanks dating from the 1970s, has been linked to the continued detention of UK-Iranian dual citizens in Iran, including charity worker Nazanin Zaghari-Ratcliffe.
“We do want to pay this debt, we recognise it’s a legitimate debt,” Ms Truss said.
Paying back the money is complicated by sanctions on Iran and banking restrictions.
“I’m also pressing for the return of our unfairly detained British nationals, including Nazanin,” Ms Truss said.