U.N. Inspector Says Iran Could Enrich Nuclear Fuel in ‘Matter of Months’

The chief United Nations nuclear inspector has widened the divide with the Trump administration over how severely the United States set back Iran’s nuclear program, declaring that it could be enriching uranium in a “matter of months” even as President Trump repeated his claim that Tehran had lost interest in the effort.

“Frankly speaking, one cannot claim that everything has disappeared and there is nothing there,” Rafael Mariano Grossi, the director general of the International Atomic Energy Agency, said in an interview with CBS News that aired on Sunday.

He said that when the United States dropped 14 bunker-busting bombs on Iran’s two uranium enrichment centers, the damage was “severe” but not “total.” In previous interviews, he said he believed that all of the more than 18,000 centrifuges, buried in underground enrichment halls, had been destroyed or damaged and knocked out of operation.

But Mr. Grossi’s analysis — one that several European intelligence agencies share — is consistent with a preliminary assessment by the Defense Intelligence Agency that was widely reported on last week. That report estimated that the strike set back the Iranian nuclear program by only a few months. The C.I.A. director said later in the week that the Iranian program had been severely damaged, and the U.S. intelligence agencies were continuing to assess the strike.

The Defense Intelligence Agency report appeared to focus on the enrichment process at the sites where the GBU-57 bunker-busters, among the most powerful in the U.S. arsenal, were used. Later analysis by outside groups suggested that the biggest loss for Iran might have been the destruction of facilities to turn that fuel into a weapon. In particular, damage to a laboratory under construction in the nuclear complex outside the ancient city of Isfahan, which is intended to convert enriched uranium into a metal, may prove a major bottleneck in Iran’s ability to convert highly enriched uranium into the metal that is needed to produce a weapon.

Rebuilding that capability, other experts have said, could take years. And much depends on whether Iran throws out I.A.E.A. inspectors — who remained in Tehran throughout the conflict with Israel earlier this month — or whether it decides to conduct its work in the open. Either way, it could be bombed again, as Mr. Trump has said in recent days he is quite willing to do.