Paris: Top US diplomat John Kerry on Saturday sought to smooth differences with France over nuclear talks with Iran, agreeing with the French that there were still gaps to overcome in the "critical weeks" ahead.
The US secretary of state said it was up to Iran to prove its peaceful intentions to the world if it wants a deal on its nuclear programme ahead of the looming March 31 deadline.
He was speaking to reporters after a 20-minute meeting with French Foreign Minister Laurent Fabius in Paris where they tried to iron out their differing views on the deal.
France has privately expressed concerns that the final agreement will not include enough iron-clad guarantees to stop Iran acquiring a nuclear bomb.
"We want an agreement that`s solid," Kerry said.
"We want an agreement that will guarantee that we are holding any kind of programme that continues in Iran accountable to the highest standards so that we know in fact that it is a peaceful programme."
Fabius emphasised that any deal to remove sanctions could not be thrashed out only between Iran and the US.
"These are multilateral negotiations and we are making sure our position is known," he said.
Fabius acknowledged that progress had been made in the months of talks since an interim deal reached on November 2013, but stressed "differences still remain" which had to be "overcome" and "there is still work to do."
In a show of unity, Kerry said he had "the same assessment" as Fabius.
"We have made progress, but there remain gaps, divergences as he (Fabius) said, and we need to close those gaps," Kerry insisted.
Having flown in from London on the last stop of a week-long trip, Kerry was also set to brief German Foreign Minister Frank-Walter Steinmeier and their British counterpart Philip Hammond on the state of the negotiations.
Kerry spent three days in Switzerland earlier this week huddled with Iranian Foreign Minister Mohammad Javad Zarif in the latest round of talks.Fabius had expressed his concerns over the deal on Friday, saying "as regards the numbers, controls and the length of the agreement, the situation is still not sufficient."
Key issues in the talks which began in late 2013 include the level of uranium enrichment that Iran should be allowed, the degree of international oversight of its programme and how long an accord should last.
"It is frankly up to Iran that wants this programme... that asserts that they have a peaceful programme to show the world that it is indeed exactly what they say," said Kerry.
Iran has long denied seeking to arm itself with an atomic bomb, insisting its nuclear programme is for peaceful civilian purposes.
Iran`s nuclear chief Ali Akbar Salehi, who met this week with the US Energy Secretary Ernest Moniz, insisted "we have overcome the stalemate over technical issues."
The unfinished plutonium reactor at Arak as well as the uranium enrichment site of Fordo had both figured high in these week`s discussions, he said.
"On enrichment and Arak, we have made very good progress. We have replied to their concerns... by making technical proposals while also defending our national interests and our nuclear industry," Salehi told Iran television, without giving specifics.
US-Iran bilateral talks are due to resume on March 15, most likely in Geneva.
Further talks between the group known as the P5+1 -- Britain, China, France, Germany, Russia and the United States -- and Tehran are also expected.