Nuclear talks between Iran and the United States "will lead nowhere" if Washington insists that Tehran drop its uranium enrichment activity to zero, Deputy Foreign Minister Majid Takhtravanchi was quoted by state media on Monday as saying.

U.S. special envoy Steve Witkoff reiterated Washington's stance on Sunday that any new deal between the U.S. and Iran must include an agreement not to enrich uranium, a possible pathway to developing nuclear bombs. Tehran says its nuclear energy program has entirely peaceful purposes.

"Our position on enrichment is clear and we have repeatedly stated that it is a national achievement from which we will not back down," Takhtravanchi said.

During his visit to the Gulf region last week, President Donald Trump said a deal was very close but that Iran needed to move quickly.

During his first, 2017-21 term as president, Trump withdrew the United States from a 2015 deal between Iran and world powers that placed strict limits on Tehran's enrichment activities in exchange for relief from international sanctions.

Trump, who branded the 2015 accord one-sided in Iran's favor, also reimposed sweeping U.S. sanctions on Iran. The Islamic Republic responded by escalating enrichment.