The United States Secretary of State John Kerry said on Sunday Iran has to make some ‘hard choices’ in order to agree on the terms of a possible final deal which is aimed to be reached by Tehran and the world powers during the Tuesday talks.
Kerry said if all the parties are prepared to make hard choices, then "we could get an agreement this week. But if they are not made, we will not,", adding that if there was "absolute intransigence" the US would walk away.
"If we don't have a deal and there is absolute intransigence and unwillingness to move on the things that are important for us, President Obama has always said we're prepared to walk away," he said.
After a 12-year of stand-off, Iran and the P5+1 group -the US, the UK, France, Russia, China and Germany- had reached a preliminary framework nuclear agreement in Switzerland on April 2.
The Western participants to the nuclear negotiations still regard that there were huge lingering issues that Tehran needs to fulfill for striking a fair deal, while Russia and China bloc was maintaining its optimism by pushing the Iranian leadership ahead of the extended talks which were started to be held from the weekend ‘till Tuesday.
Kerry told reporters in Vienna on Sunday that the parties had made "genuine progress" in the talks, but there were still "several of the most difficult issues" that hamper to strike a final agreement.
"If hard choices get made in the next couple of days, made quickly, we could get an agreement this week, but if they are not made we will not," Kerry said in Vienna, where the parties gathered to end Iran’s long disputed nuclear impasse.
"It is now time to see whether or not we are able to close an agreement," he added.
Although the US side keeps optimism, Kerry also indicated that the talks "could go either way" as he met four times with his Iranian counterpart Mohammad Javad Zarif at the weekend in the Austrian capital.
Meanwhile, the EU Foreign Policy Chief Federica Mogherini called the parties to strike the deal since she perceives the atmosphere of the talks as positive and constructive.
"The time is now... We are very close," said Mogherini, adding the atmosphere was "constructive, positive."
French Foreign Minister Laurent Fabius also raised his concerns and said a possible deal would be up to Iran’s commitment to the previously agreed terms within the preliminary deal.
"All the cards are on the table, the main question is to know whether the Iranians will accept making clear commitments on what until now has not been clarified," Fabius said.
German side also expressed the necessity of sealing a final deal as Foreign Minister Frank-Walter Steinmeier sees the talks as a unique chance which must be considered by the parties.
“I hope that it is clear to all parties in these final days that this is a unique chance that we have now," said Steinmeier as he arrived back in Vienna.
"We have a wonderful chance after 12 years of talks finally to end a long-running conflict... which would also send out a signal for the whole region." he added.
The West has long been claiming that Iran was seeking to obtain nuclear bombs through its massive nuclear activities, but Tehran denies all allegations and says its nuclear programme would aim to meet civilian needs of energy demands.
Last month, the International Atomic Energy Agency (IAEA) reported that Iran’s unwillingness to cooperate with the international investigators would cause a transparency problem.
The international watchdog said on its June monthly report on Iran that Tehran's stockpile of low-enriched uranium gas dropped below the maximum level required under 2013 level, but it insists upon a comprehensive investigation of the nuclear sites.
However, Iran’s supreme leader Ayatollah Ali Khamenei echoed the views of hardline revolutionary guards who essentially objected to the IAEA’s access to Iran’s military sites.
"Inspection of our military sites is out of the question and is one of our red lines," Khamenei said and dismissed freezing of the country’s long-standing nuclear programme for a long period of time as a necessity of prospective final agreement with the West.
Iran demands an immediate removal of sanctions, as well as the release nearly 100 billion dollars worth of its assets around the world.
But, the West still persists a complete removal of sanctions would depend on the IAEA’s full-fledged access into Iran’s nuclear facilities and freely deliver a comprehensive report on its findings which will confirm or deny the allegations attributed to Tehran.