US Secretary of State John Kerry says there has been no discussion about once-again extending the deadline for a deal on Iran's nuclear programme.
Instead, Kerry says the nuclear talks in Vienna are going to focus on "driving towards" the outline of an agreement.
"Yes we do want to get an agreement but it's just not any agreement. It has to be an agreement that works, that achieves the goal of guaranteeing that the pathways to a bomb will not and cannot be used."
Iranian parliamentary speaker Ali Larijani, a former lead nuclear negotiator, says Iran remains firm in its convictions, noting the re-establishment of stronger sanctions is something Iran knows how to live through.
"We hope that, during the talks, they behave wisely, and we hope they won't make wrong assumptions. In the past, during the war with Iraq, we managed to run the country with just six billion dollars."
The P5+1 grouping has been trying to convince Iran to open up all its nuclear facilities and limit its enrichment programs in exchange for a lifting of sanctions.
The International Atomic Energy Agency is calling on Iran to take a "strategic decision," after accusing Iran of failing to address doubts over the level of its nuclear work.
Tehran has insisted its nuclear program is strictly for civilian use only.
Monday is the deadline for reaching a deal.
