Iran said Tuesday it would not scrap any of its nuclear facilities, drawing a red line in negotiations with six world powers seeking deep cutbacks in Tehran’s atomic program in exchange for an end to crippling economic sanctions.

The statement by Deputy Foreign Minister Abbas Araghchi suggested tough talks ahead, constituting a rejection of a central demand by the six countries.

The talks are designed to build on a first-step deal that came into effect last month and commits Iran to initial curbs on its nuclear program in return for some easing of sanctions.

Iran insists it is not interested in producing nuclear weapons but the six powers want Tehran to back its words with concessions. They seek an agreement that will leave Iran with little capacity to quickly ramp up its nuclear program into weapons-making mode with enriched uranium or plutonium, which can used for the fissile core of a missile.

For that, they say Iran needs to dismantle or store most of its 20,000 uranium enriching centrifuges, including some of those not yet working. They also demand that an Iranian reactor now being built be either scrapped or converted from a heavy-water setup to a light-water facility that makes less plutonium.

Iran is desperate to shed nearly a decade of increasingly strict sanctions on its oil industry and its financial sector but is fiercely opposed to any major scaling back of its nuclear infrastructure.

“Dismantling (the) nuclear program is not on the agenda,” Deputy Foreign Minister Abbas Araghchi told reporters in Vienna.

The talks are formally led by Catherine Ashton, the EU’s top foreign policy official, and Iranian Foreign Minister Mohammad Javad Zarif. The United States, Russia, China, Britain, France and Germany are also at the table.

Ashton spokesman Michael Mann warned of the “intensive and difficult work lying ahead of us.”

Despite his colleague’s comments, Iranian Deputy Foreign Minister Abbas Araghchi said the talks got off to a “very good beginning.” He said even if they end later this week with nothing more than a future agenda “we’ve accomplished a lot.”

(AP)