"We only have 40 days left to the deadline and... None of the negotiators find (an) extension of talks appropriate," Mohammad Javad Zarif said in Vienna, a day after six hours of intense talks with US Secretary of State John Kerry.
"We share this view... And we think there is no need to even think about it," Zarif said in the Austrian capital, quoted by the state televison's website.
The comments echoed a senior US State Department official late yesterday after the talks between Kerry, Zarif and EU foreign policy chief Catherine Ashton in a Vienna hotel room.
Kerry left Vienna on this morning - after problems with his aircraft - but Zarif remained for talks with political directors from the US, Russia, Britain, China, France and Germany chaired by Ashton.
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The deal being sought, after more than a decade of rising tensions, is meant to ease concerns that Iran might be able to develop nuclear weapons under the guise of its civilian programme.
To do this, the "P5+1" powers want Iran to scale down dramatically the scope of its atomic activities, offering in return relief from painful sanctions, but Iran is resisting this.
In months of discussions since an interim agreement struck last November took effect in January, some progress has been made.
This includes possible changes in the design of an unfinished reactor at Arak so that it produces less weapons-grade plutonium, enhanced UN inspections, and alterations to the fortified Fordo facility.
The main bone of contention remains Iran's enrichment capacity, a process rendering uranium suitable for power generation but also, at high purities, for a nuclear weapon.