"If the other side enjoys the necessary will, there will be a possibility for reaching a comprehensive agreement, but if their goal is only heeding political interests of pressure groups in the western countries, there will be no possibility," Zarif said in a televised interview with Iran's state-run TV on Saturday night.
"We may face excessive demands during the negotiations, but the other side will understand in the final days that they should work with these (Iranian) people through respect and a win-win solution," he added.
Stressing that the Group 5+1 (the US, Russia, China, Britain and France plus Germany) should undertake to cancel the UNSC sanctions against Iran, Zarif said, "Any agreement with the G5+1 should lead to their going to the UNSC and presenting and approving a resolution which would annul the sanctions."
Earlier this month, Iranian President Hassan Rouhani said the US-led sanctions have harmed both the eastern and western states and their removal will help strengthen security and stability in the region.
"We have weakened and shaken the bases of sanctions and the conditions will never return to the past, we are serious and determined in the negotiations (with the world powers), but the world should know that the opportunity provided by the Iranian nation is not indefinite," Rouhani said, addressing an economic forum in Tehran.
"An agreement (between Iran and the Group 5+1) will benefit all and the western and eastern countries are telling us that the sanctions have harmed them and the removal of sanctions will benefit all," he added.
"On the other hand such an agreement will strengthen stability in the entire region and God willing, if the two sides enjoy a good will, we can reach a final settlement over this issue," Rouhani underlined.
On July 20, the deadline for reaching a final agreement on Iran's future nuclear activities was postponed by four months—until November 24—to give more time for diplomatic efforts.
Zarif and Ashton in a joint statement after over two weeks of talks stressed the need for more efforts and time to reach an agreement with the world powers over Tehran's nuclear program.
The two officials who presided the negotiating sides, emphasized at the end of Iran-G5+1 negotiations that they have held different sessions in different forms and in a constructive atmosphere to reach a final comprehensive agreement.
Due to certain differences over some fundamental issues the two sides agreed to extend the Joint Plan of Action by November 24, they added.