"We delivered the heaviest blow in that regime's history. It stands weaker than ever before," Netanyahu said in remarks at a state ceremony held in the Yad Vashem Holocaust memorial centre in Jerusalem and broadcast on Monday.

Israel has been engaged in a multi-front conflict since October 7, 2023, when Iran-backed Palestinian militant group Hamas attacked the country, triggering a deadly war in Gaza that ultimately drew in other allies of Tehran.

"For two-and-a-half years, we have been systematically crushing the Iranian axis of evil" in Gaza, Lebanon, Syria, Yemen and the occupied West Bank, Netanyahu said.

"Had we not acted, names like Natanz, Fordow, Isfahan and Parchin might have become synonymous with horror -- like Auschwitz, Treblinka, Majdanek and Sobibor," he added, comparing Iranian nuclear sites to Nazi-era extermination camps.

Israel will observe its annual Holocaust Remembrance Day from Monday evening until Tuesday evening, with memorials in honour of the six million Jews murdered by the Nazis during World War II.

The observance, held each year in April or May according to the Hebrew calendar, is separate from International Holocaust Remembrance Day on January 27.

This year's commemoration comes in the midst of a two-week ceasefire with Iran in a regional war that began on February 28 with joint US-Israeli attacks on Iran.

Despite the ceasefire, Israel continues to engage in fighting with Hezbollah militants in southern Lebanon.