Six world powers and Iran have reached a deal on the framework for comprehensive negotiations over Tehran 's nuclear program , EU foreign policy chief Catherine Ashton said Thursday . `` We have identified all of the issues we need to address in reaching a comprehensive and final agreement , '' Ashton said , speaking alongside Iranian Foreign Minister Mohammad Javad Zarif , in Vienna , Austria . `` There is a lot to do . It wo n't be easy , but we 've made a good start '' following `` three very productive days '' of talks , Ashton added . In addition to political discussions , the two sides have started technical work , Ashton said , and have set a timetable for meetings over the next four months , with a framework for further deliberations . Technical experts will meet in early March , she said , and the next round of talks between the so-called P5+1 -- the United States , China , Russia , Britain , France and Germany -- and Iran will start March 17 . Zarif then delivered the same statement in Persian . The latest talks began Tuesday . U.S. State Department spokeswoman Marie Harf said Wednesday the meetings had been `` constructive and useful . '' Interim deal . The latest talks come after an interim deal was forged in November , under which Iran agreed to roll back parts of its nuclear program in return for relief from some sanctions . That agreement came into effect in January . The challenge now is to reach a permanent deal acceptable to all sides . The United States and its allies believe Iran is trying to develop a nuclear weapon , while Tehran has said its atomic efforts are peaceful . Wendy Sherman , a senior State Department official and lead negotiator for the United States on the interim deal , told CNN 's Wolf Blitzer from Vienna this week that any final agreement will be contingent on Iran taking `` concrete '' verifiable steps that prevent it from ever obtaining a nuclear weapon . Deputy Foreign Minister Abbas Araqchi insisted Tuesday that the `` halting of Iran 's ( nuclear ) program and dismantling Iran 's nuclear facilities are not on the agenda , '' the semi-official Mehr news agency reported . Harf said specific issues such as dismantlement would be on the table in later discussions . `` We know both sides come to the negotiating table with certain positions in mind , clearly , but we do think that we have made some progress over these last few days and , hopefully , can continue to build on that going forward , '' she told reporters in Washington .
` ` We have identified all of the issues we need to address '' for final approval , says Ashton . The next round of talks will begin on September 17 , Iranian foreign policy chief says . U.S. State Department spokesman says talks have been ` ` constructive and useful '' Western powers suspect Iran wants to develop a nuclear weapon , a claim it denies .