Prime Minister Benjamin Netanyahu on Wednesday said Israel would not be bound to a nuclear deal between world powers and Iran if it enabled Tehran to develop nuclear weapons.
"An agreement with Iran that would pave the way to nuclear weapons, weapons that threaten our extinction, would not compel us in any way," Mr Netanyahu said at the Yad Vashem Holocaust memorial in Jerusalem, on the eve of Holocaust Remembrance Day.
"There is one thing that compels us – to prevent those who seek our extermination from carrying out their plot."
China, France, Germany, Russia, Britain and the EU met in Vienna on Tuesday for talks with Iran, aimed at rescuing the 2015 international deal on Tehran's nuclear programme.
The EU was acting as an intermediary for the US.
US President Joe Biden raised concern in Israel when he said he was ready to reverse the decision of his predecessor Donald Trump to withdraw from the agreement and reimpose sanctions.
The nuclear talks were set to continue on Friday.
Iran and Israel have recently attacked each other's commercial ships, reports say.
Israel believes Iran was cheating on the deal and working towards a nuclear weapon, while Tehran denies such ambitions.
"During the Holocaust, we had neither the power to defend ourselves nor the sovereignty to do so," Mr Netanyahu said at the ceremony on Wednesday.
"Today we have a state, we have a defence force, and we have the full and natural right as the Jewish people's sovereign state to defend ourselves from our enemies."
Israel in recent months has forged ties with the UAE and Bahrain, where Jewish communities were for the first time holding public Holocaust ceremonies.
"In these very moments, a museum in Dubai is holding a memorial event for Holocaust victims," Mr Netanyahu said. "Who would have believed?"
"These are indications of a welcome change in the ties between Arabs and Jews, outside of Israel and inside the country too."
There were ceremonies in Dubai and Manama on Wednesday, said Houda Nonoo, Bahrain's former ambassador to the US and a board member of the Association of Gulf Jewish Communities.
The association will host an online panel for the Jewish communities in the UAE, Saudi Arabia, Bahrain, Kuwait, Oman and Qatar, Ms Nonoo said.
"The Gulf region in general has gone through a shift in the last few years when it comes to discussing the Holocaust," she told AFP.
An annual anti-Semitism report by Tel Aviv University and the European Jewish Congress noted a decrease in physical attacks against Jews because of coronavirus lockdowns,
But there was a rise in vandalism towards Jewish property and institutions globally.
"During times of social crises, Jews are always scapegoated and targeted, and we have seen this throughout the Covid cycle," said Moshe Kantor, president of the European Jewish Congress.
Israel's Holocaust Remembrance Day ceremonies will continue on Thursday, when sirens will blare across the country for two minutes in the morning, followed by events in memory of the six million Jewish victims of the Holocaust.