"Given that there are a number of important remaining issues, the negotiations will continue in the coming days. How many days? It is unclear," the Iranian negotiator told reporters in Vienna on Tuesday, adding, though, that there is no discussion about extension of the negotiations (for a long time).
He underlined that Iran pursues "a good deal" as a principle in the talks.
The negotiator noted that the Vienna talks will go on today at the level of foreign ministers on how to "settle the remaining differences" and define the "decisive details" in a final nuclear deal.
"The progress is very tiny, but things are moving ahead," he added.
Since June 17, senior representatives from Iran, the Group 5+1 (Russia, China, the US, Britain, France and Germany) and the European Union have been in Vienna to finalize the text of a comprehensive nuclear deal.
On April 2, Iran and the six nations reached a framework nuclear agreement in Lausanne, Switzerland, that provides outlines of a final agreement, known as the Joint Comprehensive Plan of Action (JCPOA).