The United States and its allies have offered Iran state-of-the-art nuclear equipment if its scales back its nuclear activities to ensure it does not develop any weapon.
However, Iran continued to hang tough with supreme leader Ayatollah Ali Khamenei saying his country will not dismantle its nuclear program unless economic sanctions are removed first, the BBC reported.
As the clocks ticks toward the June 30 deadline for a final nuclear agreement, a draft confidential document titled "Civil Nuclear Cooperation" showed bracketed text where disagreements remained, but technical cooperation was the least issue, Fox News said.
The scope of the assistance being offered by the US and its allies may further irk critics in the US Congress, who argue that too many concessions are already being offered in the negotiating table.
The draft document vows to provide Iran with light-water nuclear reactors to keep the country from using its almost-complete heavy-water facility at Arak, which would produce sufficient plutonium for several bombs a year.
The eight-page document offers to "establish an international partnership" to rebuild the reactor into a less proliferation-prone facility while leaving Iran in "the leadership role as the project owner and manager."
The paper also strengthens a previous tentative deal on what will be done with an underground site in Fordo, which will then be used for isotope production instead of uranium enrichment.
This compromise has been criticised by congressional opponents as isotope production uses the same technology as enrichment and can easily be re-engineered to enriching uranium.
It is crucial for the facility to be repurposed as it is believed to be resistant to airstrikes, with Fordo being dug deep into a mountain. Neither the US nor Israel has set aside this option in case talks fail.
An unnamed diplomat familiar with the negotiations said China will provide assistance in re-engineering the heavy water reactor at Arak while France will help in reprocessing nuclear waste. Britain, on the other hand, will help in nuclear safety and security.
However, Ayatollah Ali Khamenei, Iran's supreme leader who has the final say on all state matters, stood firm even with the deadline just days away, saying Iran will only dismantle its nuclear program if economic sanctions are first removed, BBC reported.
He accused the US of pushing for a "complicated formula" for removing US, EU and UN sanctions which have stifled Iran's economy. The US proposed a gradual lifting of sanctions based on verification by international inspectors of Iran's compliance of its pledges.
"Lifting sanctions can't depend on implementation of Iran's obligations," Khamenei said.
Iran's parliament has green-lit a proposed law banning access to nuclear scientists and military sites. Five such scientists have been assassinated.
Khamenei also rejected a proposed halting of research and development for a decade and inspections of military sites.
"We don't accept 10-year restriction. We have told the negotiating team how many specific years of restrictions are acceptable," he said. "Research and development must continue during the years of restrictions."
"[The United States'] goal is to uproot and destroy the country's nuclear industry," he said. "They want to keep up the pressure and are not after a complete lifting of sanctions."
