The Nazis wiped out a third of the world's Jews and Mr Netanyahu's remarks illustrate how decades later, the Holocaust is still a central part of Israel's psyche.

The state of Israel was established three years after the end of the war and hundreds of thousands of survivors made their way to the country.

Speaking at the main ceremony at the Yad Vashem Holocaust memorial, Mr Netanyahu said Israel's arch-enemy Iran, as well as the Islamic State group, are "publicly striving to destroy us".

He said the lesson of the Holocaust is that "we must be able to defend ourselves by ourselves against all threats and any enemy". He said this lesson guides him "every morning and every evening".

Mr Netanyahu said Israel has transformed itself into a strong nation with one of the "strongest defensive forces in the world" and warned "those that seek to destroy us will put themselves in danger of destruction".

He said that although there has not been anything on the scale and scope of the Holocaust since the Second World War, the world has mostly stood by and not intervened in mass killings around the world from Cambodia to Sudan, and now Syria.

However, Mr Netanyahu said, "amid the darkness" there are some "points of light".

Among them, he said, was US President Donald Trump's "determined answer to the slaughter of the Syrian children by chemical weapons".

He was referring to the US missile strike earlier this month on a Syrian air base Washington believed to be the launching pad for a chemical weapons attack on civilians that killed dozens.

Israeli President Reuven Rivlin took a different approach in his remarks. He said although the Holocaust is "permanently branded in our flesh", it "is not the lens through which we should examine our past and our future".

The Israeli flag was lowered to half-mast at the beginning of the ceremony on Sunday evening as a military honour guard stood nearby.

Psalms and the Jewish prayer for the dead were recited at the podium. Survivors lit six symbolic torches to commemorate the six million dead.

The annual memorial day is one of the most solemn on Israel's calendar. Places of entertainment and restaurants shut their doors and TV stations either cease broadcasting or dedicate programming almost exclusively to Holocaust documentaries, interviews with survivors and melancholy music.

On Monday morning, Israel will come to a standstill as sirens wail for two minutes in the morning. Pedestrians typically stop in their tracks, and cars and buses halt on the streets while drivers and passengers step out of their vehicles to stand with their heads bowed.

Other ceremonies on the solemn day include the public reading of names of Holocaust victims at including Israel's parliament and elsewhere around the country.