“Even if the nuclear talks fail, our diplomacy showed the world that we are logical. We never left the negotiation table and always provided the best answer,” Rowhani, seen as a reformer in Iran, was quoted by the Nasim news agency as saying.

“Twenty-two months of negotiation means we have managed to charm the world, and it’s an art,” he said, according to Reuters news agency.

‘Decision Time’

Iran and the six powers involved in the talks – Britain, China, France, Germany, Russia and the United States – have given themselves until Monday to reach a deal, their third extension in two weeks, as the Iranian delegation accused the West of throwing up new stumbling blocks to an accord.

France’s foreign minister appeared to put pressure on the United States and Iran on Saturday to speed up talks, saying that all issues were now on the table between six major powers and Iran and that the time had to come to make a decision.

The two sides nevertheless struggled to break the deadlock in nuclear talks that has held up a historic deal that would bring sanctions relief for Tehran in exchange for curbs on its atomic program.

“Now that everything is on the table, the moment has come to decide,” Laurent Fabius said in a statement sent to Reuters.

Western and Iranian diplomats close to the talks said they expected to work well into the night in hopes of a breakthrough, perhaps as early as on Sunday, on a deal to bring sanctions relief for Tehran in exchange for curbs on its atomic program.

U.N. embargo still an ‘issue’

Among the biggest sticking points this week has been Iran’s insistence that a United Nations Security Council arms embargo and ban on its ballistic missile program dating from 2006 be lifted immediately if an agreement is reached.

Russia, which sells weapons to Iran, has publicly supported Tehran on the issue.

However, a senior Western diplomat said earlier in the week the six powers remained united, despite Moscow’s and Beijing’s well-known dislike of the embargos.

Western powers have long suspected Iran of aiming to build nuclear bombs and using its civilian atomic energy program to cloak its intention – an accusation Iran strongly denies.

Other problematic issues in the talks are access for inspectors to military sites in Iran, answers from Tehran over past activity and the overall speed of sanctions relief.

“Still have difficult issues to resolve,” Kerry tweeted on Saturday after meeting Zarif.

The two men have met nearly every day since Kerry arrived in Vienna more than two weeks ago for what was intended to be the final phase in a negotiation process lasting more than year and a half aimed at securing a long-term deal with Iran.

An agreement would be the biggest step towards rapprochement between Iran and the West since the 1979 Islamic Revolution, although both sides are likely to remain wary of each other even if a deal is concluded.