A new deadline has been set for the completion of an Iranian nuclear deal.
In failing to reach an agreement before yesterday's deadline, the P5+1 grouping an Iran have decided to push forward the negotiation window to the end of June.
The two sides have agreed to reconvene next month for a new round of talks.
US Secretary of State John Kerry says the latest round of talks have been "tough."
However, he contends "substantial progress" has been made.
"In these last days in Vienna we have made real and substantial progress and we have seen new ideas surface. We believe a comprehensive deal that addresses the world's concerns is possible, it is desirable, and at this point we have developed a clearer understanding of what that kind of deal could look like but there are still some significant points of disagreement."
Kerry hasn't revealed any details of this past weekend's negotiations in Vienna, arguing confidentiality is needed to allow for free discussions.
In Tehran, Iranian President Hassan Rouhani says most gaps have "narrowed" as part of the talks.
"In these negotiations we have not yet reached the point for a final agreement. But I can say that to reach this goal of an agreement we have taken steps forward. Today looks very different to three months ago; it's even more different to six months ago. The negotiating positions have come closer together and many of the points of disagreement have gone away."
The P5+1, which is made up of China, the US, the UK, Russia, France and Germany, have agreed with Iran to try to forge a high-level political agreement by March.
The technical details are to be sorted out by July.
As part of the new timeframe agreement, Iran will still be able to access funds which had been frozen under previous sanctions.
