Iran’s Foreign Minister, Mohammad Javad Zarif, said on Friday his country will “immediately reverse” actions in its nuclear program once US sanctions are lifted, reacting coolly to Washington’s initial offer to revive talks with Tehran aimed at restoring the 2015 nuclear deal.

US President Joe Biden’s administration said on Thursday it was ready to talk to Iran about both nations returning to the agreement, which aimed to prevent Tehran from acquiring nuclear weapons while lifting most international sanctions. Former US President Donald Trump left the accord in 2018 and reimposed sanctions on Tehran.

Tehran said the US move was not enough to persuade Iran to fully respect the accord.

When sanctions are lifted, “we will then immediately reverse all remedial measures. Simple,” Zarif said on Twitter.

Since Trump abandoned the deal, Iran has violated the accord by rebuilding stockpiles of low-enriched uranium, enriching it to higher levels of fissile purity and installing advanced centrifuges to speed up production.

Tehran and Washington have been at odds over who should make the first move to revive the accord. Iran says the US must first lift Trump’s sanctions while Washington says Tehran must first return to compliance with the deal.

However, a senior Iranian official told Reuters that Tehran was considering Washington’s offer to talk about the revival of the deal.

“But first they should return to the deal. Then within the framework of the 2015 deal, a mechanism to basically synchronize steps can be discussed,” the official said.

“We have never sought nuclear weapons and this is not part of our defense doctrine,” the Iranian official said. “Our message is very clear. Lift all the sanctions and give diplomacy a chance.”