This is unsettling news. But the Obama administration sensibly says “there is time and space” to keep working toward a diplomatic solution, despite growing pressure for military action from Israel and its supporters.

Iran’s continuing activity violates United Nations Security Council demands to halt enrichment, but as one official said, it is “not a game-changer.” The disclosure about the centrifuges is in a report expected soon from the International Atomic Energy Agency. Tehran’s nuclear ambitions are clearly dangerous to Israel and the region. But the administration argues that Iran is not on the verge of producing a weapon and that the United Nations inspectors will provide warning before it gets to that point.

Washington’s caution is well-placed, especially when set against the overheated statements of Benjamin Netanyahu, the Israeli prime minister, that time is running out. He has never warmed to the idea of negotiations between Iran and the United States and other major powers. The speculation now is that he is escalating his warnings before the United States election in a cynical gambit to get President Obama’s agreement to act against Iran soon.

An attack in this case might well make things worse. A sustained air campaign would most likely set Iran’s nuclear program back by only a few years. Moreover, the talk about using force has become a distraction, shifting attention to the Israeli-United States dispute rather than keeping it squarely on Iran.

It is disappointing that recently toughened sanctions and several rounds of negotiations have not produced positive results. If there is to be any chance of that, the world is going to have to stay united in enforcing sanctions and isolating Iran. That is why this week’s meeting in Tehran of the Nonaligned Movement was a major blow. Nations truly interested in peace should have boycotted the meeting. Instead, 120 of them sent senior representatives, including heads of state.

Some of them, like the Persian Gulf states, no doubt hedging their bets, are buying billions of dollars in new American weapons because they fear a nuclear-armed Iran. Worst of all, Ban Ki-moon, the United Nations secretary general, chose to participate even though Iran has been thumbing its nose at Security Council resolutions for nearly six years. The meeting gave Tehran the perfect propaganda opportunity to play the victim and defend a nuclear program that is indefensible.