Iran and the P5+1 group of nations will start hammering out a draft accord Tuesday aimed at ending a decade-long standoff 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.
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.
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Other sceptics of the nuclear talks, including members of the US Congress, doubt if Rouhani is genuine in seeking a lasting agreement.
The world's leading powers have long suspected that Iran is developing the capability to build an atom bomb, an allegation that Tehran has repeatedly denied.
"We want to tell the world they cannot belittle the Iranian nation; they have to respect it," Rouhani added today.
A potential deal under discussion between Iranian negotiators and counterparts from the United States, Britain, France, China and Russia plus Germany -- under the P5+1 grouping -- this week will focus on the scope of Iran's nuclear activities.
Such an agreement will aim to render Iran incapable of making any push toward atomic weapons while removing the sanctions.
The negotiators have a July 20 deadline, set by an interim deal reached in November that put temporary limits on Iran's nuclear activities in exchange for modest sanctions relief.