Envoys negotiating a deal to curb Iran�s nuclear program began a third day of talks in Vienna focused on the role of international monitors, as reports emerged of a new letter from U.S. President Barack Obama to Iranian officials.

Inspections of Iranian nuclear facilities, including military sites where past activities are suspected, have emerged as one of the last remaining logjams. On June 23, Iran�s Supreme Leader Ali Khamenei ruled out �unconventional� access by the International Atomic Energy Agency. Iran�s foreign minister, Mohammad Javad Zarif, left the talks late Sunday to return for consultations in Tehran and will rejoin discussions on Tuesday.

While diplomats representing some of the six nations negotiating with Iran were cautious over the weekend when asked about the likelihood of a deal in the next few days, the European Union�s foreign policy chief gave an upbeat assessment.

�We are near to close the deal,� Federica Mogherini said late Sunday after a meeting of foreign ministers broke up. �It is a good deal.�

U.S. Secretary of State John Kerry on Monday met with IAEA Director General Yukiya Amano at the Palais Coburg in Vienna, where the agency has increased its presence as the sides narrow their differences. Officials have said that the self-imposed Tuesday deadline for a deal is unlikely to be met.

Amid the diplomacy, the Iranian Students� News Agency reported that Khamenei had received a fifth letter from Obama earlier this month, citing senior lawmaker Mehrdad Bazarpash, who declined to say what it contained. U.S. State Department and White House officials didn�t immediately respond to requests for comment.
IAEA Role
Bazarpash told the Hamshahri newspaper that Obama speaks softly in private but makes threats in public. Those contradictions make Iranian leaders distrust U.S. statements, he said.

Previous communication between the leaders has covered the nuclear talks and major regional issues such as the fight against Islamic State, according to media reports and U.S. officials.

Although not formally part of the talks with the world powers at the table -- China, France, Germany, Russia, the U.K. and U.S. -- the IAEA will play a critical role under a deal.

Before the Islamic Republic gets full relief from global sanctions, the agency will need to finish a 12-year investigation into the possible military dimensions of its nuclear work, verify enrichment-capacity restraints have been implemented and confirm that Iran has adopted stricter monitoring rules under the so-called Additional Protocol.

While Iran has become the most-inspected country in the world, receiving 1,692 person days of IAEA inspections last year, its refusal to implement the protocol has prevented the IAEA from ruling out a military element to the nation�s nuclear activities.

By Bloomberg