“Give us the necessary answers, people and places so we can clarify the many things needed for clarification,” said IAEA Director-General Rafael Grossi on Monday.
Inspectors have also found information about a considerable amount of equipment in locations that had not been declared as places where nuclear activity was being conducted.
The developments come as the European Union mediates indirect talks between the US and Iran in an attempt to revive a nuclear deal which former US President Donald Trump exited in 2018 before imposing strict economic sanctions on Tehran.
After CNN’s Becky Anderson asked Grossi whether the IAEA will end its probe without receiving answers, he responded negatively.
“Absolutely not. We want to be able to clarify these things. So far Iran has not given us the technically credible explanations we need to explain origin of many traces of uranium, the presence of equipment at places,” he said.
“This idea that politically we are going to stop doing our job is unacceptable for us,” Grossi said.
In June, the IAEA censured Iran for traces of uranium that had been found at three undeclared sites in 2019. Iran dismissed the IAEA motion as “politicized,” and responded by removing surveillance cameras at key sites in response — depriving negotiators of up-to-date information on the country’s uranium enrichment program.
Iranian officials have demanded that the IAEA probe be dropped before Iran rejoins the nuclear deal.
But Grossi said he must have an explanation into what happened to the uranium particle traces and where they are located now. “Let us have an explanation. Where is it now? At that moment we will be able to have a report saying, yes, we have clarified this issue,” he said.
Since Trump withdrew from the nuclear deal and launched an aggressive sanctions regime in May 2018, Tehran has enriched uranium at higher levels and at an increasing speed.
Current US President Joe Biden restarted talks to restore the deal with Iran nearly a year and a half ago. Progress has been slow, but there have been signs of progress in recent weeks.
The UN nuclear watchdog said in June that Iran was weeks away from having a “significant quantity of enriched uranium,” but added that it “does not mean having a bomb.”