The head of the UN’s nuclear agency signaled Wednesday that Iranian nuclear enrichment sites would be visited by his inspectors, a key component in the interim deal between the United States and Iran to reach an end to the war.

Axar.az reports, citing the Associated Press, the comment by International Atomic Energy Agency head Rafael Mariano Grossi was the firmest yet from the United Nations agency, which is viewed as key in determining the status of Iran’s nuclear stockpile.

The US and Iran offered contradictory remarks Tuesday about whether those sites would be inspected.

“I can understand political statements, they are part of the reality, but the fundamental thing I would like to remind you and draw your attention to is that there has been a Memorandum of Understanding, signed by both presidents,” Grossi told journalists at a news conference at the tsunami-hit Fukushima Daiichi nuclear power plant.

The accord “explicitly states that the nuclear activities that are going to be carried out with the regards of the nuclear material facilities will be supervised by the IAEA — in all letters,” he said.

Grossi added: “Obviously, to do that, we have to inspect. Whether this happens the day after tomorrow or in one week or in ten days, it’s important, but not essential. This is going to happen.”

Those inspections are key for the deal, which calls for Iran’s stockpile of uranium to be “downblended” from highly enriched levels.