Talks between experts from the six powers and Iran are being held on the sidelines of the UN General Assembly's ministerial meeting.
Iranian President Hassan Rouhani has suggested that the pace of the talks must be sped up if the deadline for the November 24 final agreement is to be reached.
This comes after an expected meeting of foreign ministers was called off on Friday.
Rouhani calls for courage in accelerating the negotiations.
"Today, there is a serious intent, which is quite evident, to perceive even through the words and these words can not be privy of serious will, so we do feel that the serious will does exist. But on this important path, we must show courage. Every side must show courage."
The talks between Iran and the six powers have been going on for years without much progress.
The Iranian government insists its right to develop enriched uranium, activities that the West suspect to be a nuclear weapons programme in disguise.
