Hassan Rouhani (file photo)
Iran and the P51 group of nations will start hammering out a draft accord on Tuesday aimed at ending a decade-long stand-off over suspicions that the Islamic republic is concealing military objectives.
"We have nothing to put on the table and offer to them but transparency. That's it. Our nuclear technology is not up for negotiation," Rouhani, referring to the West, said in remarks broadcast on state television.
"Iran will not retreat one step in the field of nuclear technology... we will not accept nuclear apartheid," he said.
The self-declared moderate president has faced a battle from domestic critics of his diplomatic outreach since taking power last August.
Hardliners accuse Rouhani of making concessions for little gain under talks that have started to reverse the political isolation Iran grappled with under his hardline predecessor Mahmoud Ahmadinejad.
Other sceptics of the nuclear talks, including members of the US Congress, doubt Rouhani's sincerity in seeking a lasting agreement.
The world's leading powers have long suspected that Iran is developing the capability to build an atomic bomb, an allegation Tehran has repeatedly denied.
"We want to tell the world they cannot belittle the Iranian nation; they have to respect it," Rouhani said on Sunday.
Iran has suffered years of economic hardship exacerbated by international sanctions designed to coerce Tehran into curbing its nuclear work.
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Iran Won't Accept 'Nuclear Apartheid': President Hassan Rouhani