Iran needs stronger guarantees from Washington for the revival of a 2015 nuclear deal, its foreign minister said in Moscow on Wednesday, adding that the U.N. atomic watchdog should drop its "politically motivated probes" of Tehran's nuclear work.

Earlier in the day, the head of Iran's Atomic Energy Organization, Mohammad Eslami, said that if the International Atomic Energy Agency did not close the investigation into Tehran's undeclared activities, "there will be no implementation of the agreement."

And the website "Iran International" quoted Eslami as saying that Iran "does not possess undeclared nuclear sites... The IAEA's questions must be closed before all parties return to the JCPOA, otherwise there will be no day of re-implementation."

Islami considered that the IAEA's questions "come in continuation of those alleged military readings", expressing his rejection of the documents submitted against Iran about three sites. "Iran does not have an undeclared nuclear site in principle," he said.

He continued, "Negotiation is a give and take, not a construction article decision, where you can say nice things."

"The nuclear deal to happen the global nuclear watchdog must put an end to its probing of Iran nuclear sites, "Raisi asserted at a news conference in Tehran on Monday, marking a year as president.

Yesterday, the Iranian Tasnim Agency quoted a spokesman for the Iranian Atomic Energy Organization as saying that Tehran would not accept the "excessive" demands of the International Atomic Energy Agency of the United Nations.

"We consider the demands of the IAEA to be excessive because their implementation is impossible because of the sanctions. If they lift the sanctions, Iran will respond in kind," Tasnim news agency quoted Behrouz Kamalvandi as saying.

After months of indirect talks, Tehran and Washington are struggling to revive the 2015 nuclear deal. The main sticking point is Tehran's insistence that the Atomic Energy Agency close its investigations into uranium traces found at three undisclosed sites before the nuclear deal was revived.

On Monday, Iranian President Ibrahim Raisi announced that reviving the agreement on his country's nuclear program is linked to the International Atomic Energy Agency's closing of the file of Iranian sites suspected of witnessing unauthorized activities, with the negotiations between Tehran and major powers reaching critical stages.

The issue of previously finding traces of nuclear materials at three sites, which Tehran did not claim to have witnessed such activities, raises tension between Iran on the one hand, and Western powers and the United Nations agency. The amount of Uranium traces found at the sites prompted the head of the IAEA to warn that “only countries making bombs” are exhibiting this level of activity.    

While Iran considers this file "political", Western countries, particularly the United States, are calling on it to cooperate with the agency to put an end to these suspicions.

Raisi's comments came while Tehran is studying the US response to Iran's proposals in response to a "final" draft presented by the European Union with the aim of completing indirect talks between the two parties that began last year with the aim of reviving the 2015 agreement, from which Washington withdrew in 2018.

If the US and Iran do not reach an agreement, Iran could become a nuclear state within days, experts warn.

The deal could also supply over 1 million daily barrels to the global market, offsetting high energy prices caused by the war in Ukraine. The European countries are pushing Washington to reach a deal soon, otherwise the US allies at the forefront of the Russian war in Ukraine could face disaster in the coming months.