"I believe they have realized – sanctions, pressure and an agreement will not go together," Zarif told reporters during a press conference at Beau Rivage Hotel in Lausanne, Switzerland.
The top Iranian diplomat was speaking after a meeting with his counterparts from Germany, France and the United States. He said Paris and Berlin seemed determined to reach a lasting agreement.
"I believe our negotiating partners also need to make this decision," Zarif said.
The West seeks assurance that Iran is not building an atomic bomb under the guise of a peaceful nuclear energy program. Tehran has been increasingly under pressure to hammer out a framework deal as a new deadline approaches. This round of negotiations wraps up on Sunday.
An agreement between Tehran and the P5+1 group — Britain, France, China, Russia, the United States and Germany – could help ease international sanctions against Iran in exchange for curbs on its nuclear research and increased monitoring of nuclear facilities.
"We had excellent meetings, and we made a lot of progress… We discussed all the issues that need to be resolved," Zarif told reporters.
"I think we can on fact make the necessary progress to be able to solve all the problems and to start writing them down in the text that will be the final agreement," he added.
Tehran is currently in talks with the P5+1 group of international mediators comprising Russia, the United States, China, France, the United Kingdom and Germany, in an attempt to find a comprehensive deal, ensuring a peaceful nature of the Iranian nuclear program.
A new round of Iranian nuclear talks kicked off in Lausanne on Thursday and expected to conclude on Sunday.