Netanyahu was speaking at the start of Israel's Holocaust Remembrance Day, which commemorates the murder of six million Jews by the Nazis during World War II, and is observed every year in April or May according to the Jewish calendar. The International Holocaust Remembrance Day is marked on January 27.

"The regime in Iran is a threat to our destiny, to our very existence, and to the fate of all humanity," Netanyahu said in a solemn address at Yad Vashem, the Holocaust memorial centre in Jerusalem.

"This is what will happen if it obtains nuclear weapons. If we lose this battle, the Western nations will be next," Netanyahu said, using the memorial day to deliver a political message.

"Israel will not lose, will not give in, and will not surrender," he said.

Netanyahu's comments come as arch-foes the United States and Iran are engaged in indirect talks over the Iranian nuclear programme.

Western powers and Israel, considered by experts the only nuclear-armed state in the Middle East, have long accused Tehran of seeking nuclear weapons.

Iran has always denied the charge, insisting its nuclear programme is for peaceful purposes only.

Netanyahu has repeatedly vowed that he would not allow Iran to have nuclear weapons. The New York Times reported last week that US President Donald Trump had dissuaded Israel from striking Iran's nuclear sites in the short term.

In his remarks at Yad Vashem, Netanyahu also compared Palestinian militant group Hamas, whose October 7, 2023 attack on Israel sparked the Gaza war, to the "Nazis, like Hitler".

"They want to kill, to destroy all the Jews," he said.

"They openly declare their intent to destroy the Jewish state, and that will not happen!"

The Israeli military last month resumed its campaign against Hamas in Gaza Strip after a two-month ceasefire.

Earlier on Wednesday, an Israeli government body supporting Holocaust survivors said 120,507 of them were living in Israel, down nearly 10 percent from last year's figure.

In April 2024, the number stood at 133,362 survivors of the Nazi persecution of Jews eight decades ago.

As part of the remembrance day, Israel will observe on Thursday a two-minute silence as sirens wail across the country in memory of the victims of the Holocaust.