A senior negotiator described as "complicated and extensive" the process of working out the details of the final nuclear deal, especially regarding sanctions-related terms.
Tehran and the major powers reached an agreement on the outline of the final accord earlier this month and announced the breakthrough in a statement released in the Swiss city of Lausanne.
"As (the lifting of) sanctions is a multi-faceted issue, drafting the details is a complicated and extensive task," Abbas Araqchi said, adding that because sanctions have been imposed by different authorities, some by the US, some Europe and the rest by the European Union, "there are many different aspects to them," IRNA reported.
The first round of nuclear negotiations to start writing the text of the final agreement ended on Friday in Vienna.
During the three-day discussions, Iranian negotiators met European Union political director Helga Schmid on the first day and the US delegation headed by Under Secretary of State Wendy Sherman on the second day.
A meeting between representatives of Iran and the P5+1 (the five permanent members of the United Nations Security Council plus Germany) marked the end of the negotiations.
"Therefore, writing down the details is not that easy. But we have started the work and we hope to be able to get through it within the due time."
Iran and its international negotiating partners are trying to finalize the details of the comprehensive deal by a self-imposed end-June deadline.
Need for Clarification
Despite being difficult, "all economic and financial sanctions must be removed on the same day the agreement comes into effect," he stressed, adding, "And this is (the condition) based on which we reached the preliminary agreement and we are trying to get it written in the text."
Given the misunderstandings arising between Iran and United States and the differing interpretations by the two sides regarding the terms of the statement, particularly those relating to sanctions, it was crucial to first clarify the sanctions-related provisions.
"So sanctions formed the main basis of in Vienna talks," the negotiator said.
Iran insists that sanctions should be lifted as soon as any final deal takes effect, while the US wants sanctions to be phased out gradually.
Describing the negotiations as "good and useful", the deputy foreign minister said, "It is a difficult work and we will (have to) proceed very slowly."
"We are trying to maintain a constructive atmosphere in the talks and pursue them in the right direction and according to the frameworks and solutions agreed on in Lausanne," Araqchi said.
The next round of negotiations is set to be held on the sidelines of the 2015 NPT review conference in New York next week.
