The chief negotiators of Iran and six world powers met on Friday at 22:30 local time in the sixth such meeting since the start of the latest round of talks on Wednesday.

Zarif also met with France’s representatives at the talks. In the previous nuclear negotiations in early November, France was said to be the main reason behind the failure of the six powers and Iran to reach an agreement.

The present round of talks was scheduled to end on Friday, but were extended into Saturday.

While Russian Foreign Minister Sergey Lavrov has already arrived in Geneva, the foreign ministers of the US, China, Britain, France and Germany are also scheduled to join the negotiations.

After his fifth session with Ashton on Friday, Zarif told reporters that the two sides “have moved forward up to 90 percent” in the course of their nuclear negotiations.

Zarif also noted that only “one to two issues” need to be resolved.

The diplomats present at the talks, including the Iranian negotiators, have expressed satisfaction over the progress made in the course of the Friday meetings.

Seyyed Abbas Araqchi, an Iranian negotiator and the deputy foreign minister for legal and international affairs, says Iran and the sextet of powers have been working on the text of a joint document since Thursday morning.

He noted that Iran is moving closer to an accord with the six world powers but some important issues still remain unresolved between the two sides.

Informed sources said on Friday that the six world powers have accepted the Islamic Republic’s right to enrich uranium. The issue has been Iran’s key red line and a major bone of contention between the two sides over the decade-long standoff.

Commenting on the reports about the consensus on the enrichment right, Araqchi said, "I neither confirm nor deny" that differences over the issue have been resolved "because the negotiations have not yet finalized."