In another indication that Iran may be seeking to de-escalate its confrontation with the United States, United Nations nuclear inspectors are seeing some signs that Tehran is lifting its foot, if just a bit, on the acceleration of its nuclear program.
Rafael Mariano Grossi, the director general of the International Atomic Energy Agency, said in an interview that Iran was still adding to its supply of uranium enriched to 60 percent purity — just below what it would need to produce nuclear weapons. But the surge in production that began just after the Israeli military action in Gaza in response to Hamas’s Oct. 7 terror attack appears to have abated, he said.
“There is a bit of a slowing down,” Mr. Grossi said, adding, “They are still adding to the stockpile but more slowly.”
Mr. Grossi has been engaged in years of jousting with Iran over the restrictions it has placed on inspectors, and its dismantling of cameras and other sensors at key locations in the country’s now vast — and dispersed — nuclear fuel production program.
Divining Iran’s intentions from its enriched uranium production is difficult, but over the years the rate has been more closely linked to the level of tension in Iran’s relationships with the United States and Israel than it has been with the technical necessities of production.
In recent days, after a drone attack linked to an Iran-allied group killed three American service members in Jordan, Tehran has repeatedly signaled that it does not want a direct confrontation with the United States.
On Tuesday, the Iran-backed militia that appears responsible for the drone attack, Kata’ib Hezbollah, or Brigades of the Party of God, said it was giving in to pressure from Iran and Iraq to cease targeting American forces. The militia is the largest and most established of the Iran-linked groups operating in Iraq.
It is not clear precisely when the slowdown in uranium production began, but it appears Iran has grown concerned that its nuclear enrichment program could become a major military target. Israel has regularly run exercises to simulate bombing it, and the United States engaged in actions for more than 15 years to sabotage the program.
Iran has denied that its goal is to produce a nuclear weapon, and so far intelligence officials have said there is no evidence it is racing to produce one.
Iranian authorities appear to have carefully calibrated their enrichment activities to stay just below the threshold of bomb-grade material, which is usually defined as uranium enriched to 90 percent purity. (It is possible to build a weapon with fuel enriched below that level.) Last November, the I.A.E.A. reported that the country had 128 kilograms of 60 percent enriched uranium.
Starting in June, it reduced its production dramatically, in what appeared to be a quiet signal to the United States. But it surged in December, and only recently slowed again.
None of these variations affect the larger picture: Iran now has more uranium that is close to bomb grade than it has in years, after a 2015 nuclear agreement forced it to give up 97 percent of its stockpile. President Trump withdrew from that accord in 2018, triggering the current buildup. In addition, Iran has begun to build underground facilities that are harder to bomb.