Iranian Foreign Minister Mohammad Javad Zarif insisted on Monday that his country has the "absolute right" to enrich uranium on its soil, ISNA news agency reported.
"The mastery of civil nuclear technology, including the enrichment of uranium, on Iranian soil is the absolute right of Iran," Zarif said at a meeting in Tehran with the visiting Swiss deputy foreign minister, Yves Rossier.
"The events of recent years have shown that the approach of threats and sanctions have not ensured the interests and objectives of the other party, and the continuation of this approach is the repetition of past mistakes which cannot prevent Iran from mastering civilian nuclear technology," he added.
The West and Israel have long accused Iran of seeking to develop nuclear bombs in the guise of a civilian programme, charges Tehran has always vehemently denied
Iran and six world powers — Britain, China, France, Germany, Russia, the United States — are set to resume negotiations in Geneva on October 15 to try to find a solution to the nuclear issue.
They would be the first talks between Iran and the six since the election in June of moderate President Hassan Rouhani, who has called for a speedy settlement of an issue that has been stalled for eight years.
At meetings in Almaty this year, the six proposed Iran suspend uranium enrichment at the 20 percent level it says it needs for a medical research reactor, and to halt enrichment at its underground plant at Fordo.
In return, they would ease some sanctions on trade in gold and petrochemicals.
However, Zarif said on Sunday the offers were now "history" and that the group "should come to the negotiating table with a new approach".
US Secretary of State John Kerry on Monday urged Iran to come up with new proposals.
"The group of six put a proposal on the table at Almaty and I don't believe as of yet Iran has fully responded to that particular proposal. So I think we are waiting for the fullness of the Iranian difference in their approach now," Kerry told reporters in Indonesia after meeting Russian Foreign Minister Sergei Lavrov.
"So what we need are a set of proposals from Iran that will fully disclose how they will show the world that their programme is peaceful," he added.