Olmert said in the interview that was shown on Israeli television: "The most that we tried to get for ourselves is to be able to live without terror. But we never threatened any nation with annihilation.
"Iran, openly, explicitly and publicly threatens to wipe Israel off the map. Can you say that this is the same level, when they are aspiring to have nuclear weapons, as America, France, Israel, Russia?"
Speaking in Germany on Tuesday, Olmert denied he had "outed" Israel's nuclear programme.
"Israel has said many times, and I also said this to German television in an interview, that we will not be the first country that introduces nuclear weapons to the Middle East," he said after meeting Angela Merkel, the German chancellor.
"That was our position, that is our position - nothing has changed."
On his first official trip to both countries since taking office in May, Olmert held talks on Tuesday with Merkel.
He will meet Romano Prodi, the Italian prime minister, on Wednesday. He is expected to press both leaders for economic sanctions against Iran, should Tehran refuse to abandon its nuclear programme.
Mordechai Vanunu, the whistleblower who gave Israeli nuclear secrets to the British paper The Sunday Times in 1986 and served an 18-year sentence for his disclosures, said on Tuesday he hoped Olmert's comment was not a mistake, but rather "the beginning of a policy change" that would see Israel openly acknowledge its nuclear weapons.
One Israeli newspaper wondered whether the list of countries raised the possibility that "nuclear weapons" could apply to Iran, not the list including Israel - but the grammatical nuance was lost on the rest of the Israeli media and political world.
Yossi Beilin, an opposition politician and head of the dovish Meretz party, criticised what he termed Olmert's "carelessness".
Unfit to serve?
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".
Silvan Shalom, a former foreign minister and member of 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?"
Abdul Rahman al-Attiyah, the secretary-general of the Gulf Co-operation Council, said: "The United States should not apply double standards since it calls for sanctions on countries that have nuclear programmes that we have not ruled out are framework of nuclear weapons."
Speaking to reporters at a one-day conference in Kuwait to enhance cooperation between the Gulf states and Nato, al-Attiyah said: "I believe it is time now for the international community to see that peace and security are now threatened by this announcement."