In an interview with a German television station broadcast Monday, Olmert appeared to list Israel among the world's nuclear powers, violating the country's long-standing policy of not officially acknowledging that it has atomic weapons.
Asked by the interviewer about Iran's calls for the destruction of Israel, Olmert replied that Israel has never threatened to annihilate anyone.
"Iran openly, explicitly and publicly threatens to wipe Israel off the map," Olmert said. "Can you say that this is the same level, when you are aspiring to have nuclear weapons, as America, France, Israel, Russia?"
Israel, which foreign experts say has the sixth-largest nuclear arsenal in the world, has stuck to a policy of ambiguity on nuclear weapons for decades, refusing to confirm or deny whether it has them.
The comments came days after incoming U.S. Defense Secretary Robert Gates, in testimony to a Senate committee, identified Israel as a nuclear power. Gates' comments irked Israeli officials.
With Olmert's quote featured on the front pages of all of Israel's major papers Tuesday and with political rivals calling for his resignation, aides to Olmert — who was in Berlin Tuesday on a state visit — hurriedly said the remark had been misinterpreted.
Olmert spokeswoman Miri Eisin said the prime minister had been listing not nuclear states but "responsible nations."
"The prime minister stated clearly that Israel will not be the first to introduce nuclear weapons into the Middle East," Eisin said, adding that the quote had been "taken out of context."
But the damage control did little to stem the uproar, adding to the already considerable political difficulties of a prime minister whose popularity has plunged since last summer's costly and inconclusive war in Lebanon.
In a front-page editorial, the daily Haaretz slammed Olmert, who it said "preferred to forget that he was prime minister, not another commentator" or minor politician.
Opposition lawmaker Yossi Beilin, head of the dovish Meretz party, criticized what he termed Olmert's "carelessness." Together with Olmert's perceived failures of leadership during the Lebanon war, Beilin said, "it might be an indication that he isn't fit to serve as prime minister."
Former Foreign Minister Silvan Shalom, of the hardline Likud, another opposition party, said the comment could hurt Israel's attempt to get the international community to prevent Iran from obtaining nuclear weapons.
Shalom said Olmert "gave tools" to Israel's enemies, allowing them to say, "Why are you dealing only with Iran while Israel is confirming that it has the same kind of weapons?"
One of Olmert's few defenders was Binyamin Ben-Eliezer, a member of Olmert's coalition government and a former defense minister. "There was no damage here," Ben-Eliezer told Army Radio.
Mordechai Vanunu, the whistleblower who gave Israeli nuclear secrets to the British paper The Sunday Times and served an 18-year sentence for his disclosures, said he hoped Olmert's comment wasn't a mistake, but rather "the beginning of a policy change" that would see Israel openly acknowledge its nuclear weapons.
Vanunu, who is still under tight security restrictions that bar him from leaving the country, said the authorities should now "end my case, which is making a mockery of the world."
Shlomo Brom, an expert on strategic affairs at Tel Aviv University's Institute for National Strategic Studies, said Olmert had simply been misunderstood. "This is much ado about nothing," Brom said.