Iran follows the guidelines of Islamic ideology and the holy book Quran in the course of negotiations with the Group 5+1 (Russia, China, the US, Britain, France and Germany), Ayatollah Mohammad Emami Kashani said in an address to worshippers at Friday prayers service in Tehran.
By relying on that ideology, the Iranian negotiators have remained steadfast in their stances and will never retreat from their positions, which are based on the Iranian nation's dignity, the cleric added.
Iran and the Group 5+1 (alternatively known as P5+1 or E3+3) have been negotiating over the past 22 months to end more than a decade of standoff over Tehran's civilian nuclear program once and for all.
The two sides are busy negotiating in the Austrian capital of Vienna to clinch a nuclear deal.
On Tuesday, the parties gave themselves an extra week beyond an end-June deadline to nail down details of the long-awaited accord.