Continued pressures and an agreement don't go together, Zarif told IRIB in Vienna on Friday, after a meeting with Austrian President Heinz Fischer.
The Iranian minister is in Austria in a final round of diplomatic talks with the Group 5+1 (Russia, China, the US, Britain, France and Germany) for clinching a comprehensive deal on Tehran's nuclear program.
"Much progress has been made, but there still exist various technical and textual subjects," Zarif said of the process of drafting the long-awaited deal, dubbed the Joint Comprehensive Plan of Action (JCPOA).
"As I have mentioned several times, the Western countries need to make their political decision as to whether they are after an agreement or seek to continue pressures," he underlined.
Zarif said the West has repeatedly claimed to have the necessary political will to clinch a deal, but added that such determination has not been put into action.
"Sometimes, problems emerge in drafting (the text of the deal) that may indicate that there is an inclination to retain the (anti-Iran) sanctions, often in bureaucracies. We have to overcome these problems, too," the top Iranian diplomat added.
Iran and the Group 5+1 ((Russia, China, the US, Britain, France and Germany) 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.