TEHRAN (FNA)- Iran's senior negotiator Seyed Abbas Araqchi said drafting a final nuclear agreement between Iran and the world powers is making progress, but at a very slow pace.

"The progress in the nuclear talks is made very slowly due to the vastness and complexity of the issues," Araqchi, also Iran's deputy foreign minister for legal and international affairs, told reporters on Friday.

He noted that Iran and the Group 5+1 (the US, Russia, China, France and Britain plus Germany) have worked on drafting the main text and annexations of the final deal at expert and deputy foreign ministers' levels over the past three days.

Araqchi, meantime, announced that the new round of negotiations on the final nuclear deal will resume in Vienna, Austria, on May 26.

Araqchi, Iranian Deputy Foreign Minister for Europe and America Majid Takht Ravanchi and their counterparts in the G5+1 started the fourth round of nuclear talks in Vienna on Wednesday and it lasted until Friday.

On may 12, Araqchi said a major part of the contents of the draft nuclear deal between Tehran and the world powers had been agreed, while differences were still in place over one part.

"We have now a text that a major part of it, even all its phrases, has been agreed but a part of it is still a source of difference," Araqchi said in an interview with the state-run TV upon arrival at Vienna airport at the time.

"In certain paragraphs, there is difference on one phrase and in certain other paragraphs, one sentence and in certain parts, the whole phrase has not been agreed; yet now a major part has ended," he added.

Araqchi expressed the hope that Iran and the G5+1 would reach a final agreement before the July 1 deadline.

After nine days of hard work in Lausanne, Switzerland, Iran and the G5+1 reached an understanding on April 2 which laid the ground for them to start drafting the final nuclear deal over Tehran's nuclear energy program ahead of a July 1 deadline.

Reading out a joint statement at a press conference with EU foreign policy chief Federica Mogherini in Lausanne on April 2, Iranian Foreign Minister Mohammad Javad Zarif said according to the agreement, all the US, EU and UN Security Council sanctions against Iran would be lifted under the final deal.

Talks are underway among the delegations of the seven nations to draft the final deal.

By Fars News Agency