'Tricky Issues' and Cautious Optimism: Iran Nuclear Talks Continue as Deadline Approaches Fast

Negotiations between the foreign ministers from six world powers and their Iranian counterpart have become more urgent as a self-imposed deadline to secure an agreement over Tehran's nuclear program by tonight fast approaches.

The P5+1 — the US, UK, France, Germany, China, and Russia — and Iran must reach a framework agreement by Tuesday at midnight Central European Time (6 ET) over a deal which would curtail the Islamic Republic's nuclear enrichment activities in exchange for economic sanctions relief. Even at this crucial stage, differences between the parties still persist after six days at the negotiating table in Lausanne, Switzerland.

These issues could scupper the deal and and prevent a comprehensive agreement from being reached after the framework stage, although officials have also told the Associated Press that a joint statement will be issued today, where parties will agree to continue negotiations aimed at reaching the final deadline at the end of June.

Today began on a positive note when Russian Foreign Minister Sergei Lavrov offered some optimism, despite leaving the talks on Monday and announcing that he would only rejoin if there was a realistic chance of securing a deal. Lavrov told reporters: "The chances are high. They are probably not 100 percent but you can never be 100 percent certain of anything. The odds are quite 'doable' if none of the parties raise the stakes at the last minute." Lavrov claimed he would be rejoining the talks in Switzerland today.

China's Foreign Minister Wang Yi said on Monday he was "cautiously optimistic," although US Secretary of State John Kerry told CNN that there were "tricky" issues persisting. "We are working very hard to work those through. We are working late into the night and obviously into tomorrow. We are working with a view to get something done," Kerry said. Kerry's spokeswoman Marie Harff said that there was a 50-50 chance that parties would reach an agreement on Tuesday.

There is added pressure from the Republicans in the US Congress, who warned that if no agreement is reached they will consider imposing fresh sanctions on Iran. House Speaker John Boehner said that the sanctions would "come and they're going to come quick."

Related: Israel denies report it spied on Washington to derail Iran nuclear talks. Read more here.

Differences between the world powers surround three key issues. Firstly, Iran wants the economic sanctions to be lifted immediately once an agreement has been reached, although the P5+1 favours a more phased out approach. Secondly, after the 10 years where Iran's nuclear activities would be curtailed, the country wants to see all limits lifted and enabled to pursue nuclear research and development. Thirdly, there is the issue as to whether world powers could restore the sanctions if Iran violates the deal.

"There will be no agreement if the sanctions issue cannot be resolved," Majid Takhteravanchi, an Iranian negotiator, promised the country's Fars news agency. "This issue is very important for us."

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