Israeli Prime Minister Benjamin Netanyahu opened the country's annual memorial day for the 6 million Jews killed in the Holocaust by issuing a stern warning Sunday to the world to learn the lessons of the past and prevent another Holocaust.

At the opening ceremony at the Yad Vashem Holocaust memorial, Netanyahu linked the Nazi genocide to Iran's suspected drive to acquire nuclear bombs and its leaders' repeated references to the destruction of Israel and its denial of the Holocaust. Netanyahu said that just like before World War II, there were those in the world today who refused to face uncomfortable truths.

"In this place I have said many times that we must identify an existential threat in time and act against it in time and tonight I ask 'why in the years before the Holocaust did most of the world's leaders not see the danger ahead of time?' In hindsight, all the signs were there," he said.

"Has the world learned a lesson from the mistakes of the past? Today we are again faced with clear facts and before a real danger. Iran calls for our destruction, it develops nuclear weapons."