Negotiators plan to meet again next week in Geneva, after failing to reach an interim deal because of what Secretary of State John Kerry has described as a difference in only four or five phrases. The prospect that a deal could be reached soon has provoked a storm of protest from Israel and criticism from Republicans and some Democrats.

The I.A.E.A. report does not show anything close to an across-the-board freeze or rollback in Iran’s program. Iran continues to produce low-enriched uranium around the pace it has in the past. But inspectors, who completed their last visit to Iran just days ago, said that no more new, highly efficient centrifuges that the country has invested heavily in building were installed at its two main nuclear sites. Those centrifuges, called the IR-2, were particularly worrisome because they would shorten Iran’s “breakout time” to build a weapon, if they were operating.

The report said that Iran, at its Fordo plant near the city of Qum, had not put more of its existing 2,710 centrifuges into operation. Only 696 of the installed machines, all of the older IR-1 model, are actually enriching uranium — well below the plant’s capacity.

Iran’s stockpile of its most worrisome category of uranium — enriched to nearly 20 percent, close to bomb grade — increased only modestly. Since the last quarterly accounting, Iran has added roughly 10 kilograms, or about 22 pounds, of uranium enriched to 20 percent purity to its stockpile, bringing its total of the medium-enriched material to roughly 196 kilograms, or about 432 pounds. Iran is turning most of that uranium into fuel for reactors, which diminishes its threat as a bomb fuel.

The report also found that Iran had performed only minor work on the heavy-water reactor at Arak, a facility that has raised alarm because it could eventually produce plutonium, giving Iran a second source of bomb fuel.

Nader Karimi Joni, a political analyst close to the Rouhani administration, said, “It is fair to say that Iran is showing good will, just like the European Union and the United States have done.”

Still, experts on Iran cautioned against imputing a political motive to what is fundamentally a technical decision.