Foreign Minister Hossein Amir-Abdollahian's comments came a day after the US pointman on Iran, Rob Malley, said the odds of success were lower than the odds of failure.

"The most important thing is that the economic sanctions need to be lifted in an effective way. The most important thing is that the maximum pressure policy of the Trump era... needs to be removed," Amir-Abdollahian said at the World Economic Forum in Davos, Switzerland.

"If you are talking about direct talks then you have to prove to us that you're different from President Trump," he said.

The 2015 nuclear deal -- brokered under then president Barack Obama with the blessing of European powers, China and Russia -- promised economic relief for Iran which, inspectors said, had been complying with the accord's severe curbs on its nuclear program.

Trump withdrew in 2018 and imposed sweeping unilateral sanctions including on Iran's oil, vowing to bring Tehran to its knees.

Malley, who has led more than a year of indirect talks with Iran in Vienna, said Wednesday that Trump's approach had demonstrably failed, with Iran stepping up nuclear work since the United States withdrew from the deal.

He told US lawmakers that Biden's administration still supported the 2015 accord and was ready to lift sanctions if it secures an agreement.

But he said "excessive Iranian demands" made the odds of success lower.