WASHINGTON – Israel’s US envoy called on the world Thursday to prevent Iran from perpetrating another Holocaust.“We have to prevent a second Holocaust from happening,” Ambassador Michael Oren told The Jerusalem Post following a Holocaust Remembrance Day ceremony in the Capitol rotunda. “When Iran says it wants to destroy the State of Israel, which just happens to have six million Jews, we have to take it seriously.” Oren stressed that “we can never compare the Holocaust to anything. It’s in a league by itself. It’s uniquely horrific.”But he added, “We also have to look for similarities.”The historian-turned-diplomat described the shared circumstances of the present day and the 1930s: economic crises, a war-weary public, a radical regime plotting domination, the Jews depicted as a cancer.“It’s not a coincidence that Iran’s denying the Holocaust while seeking to perpetrate a second one,” he said.Oren delivered a similar message at the Capitol ceremony, though he noted an important difference between action against the Holocaust in the past and toward Iran now.“The United States is not, is not watching passively. On the contrary, the White House and the Congress are leading the world” in imposing sanctions, keeping all options on the table and declaring Israel’s right to defend itself, he said.One of the key forces behind those sanctions – the US Treasury – was represented at the ceremony as well.Treasury Secretary Timothy Geithner delivered the keynote address, in which he described the world’s “most creative and most effective system of financial sanctions” to keep Iran from pursuing its nuclear ambitions as “crucial to thwarting those who would kill in the name of hatred.”John Boehner, speaker of the US House of Representatives, and Per Westerberg, speaker of the Swedish Parliament, attended the ceremony as well.Westerberg’s presence honored Raoul Wallenberg, the Swedish diplomat who risked his life saving thousands of Jews during the Holocaust and later disappeared. His fate remains unknown to this day.Earlier this week, the US House of Representatives voted unanimously to award Wallenberg the Congressional Gold Medal.US President Barack Obama marked Holocaust Remembrance day with calls to combat Holocaust denial and anti-Semitism, as well as for vigilance against current and future atrocities."As societies, we must stand against ignorance and anti-Semitism, including those who try to deny the Holocaust," Obama said in a statement issued Thursday. "As nations, we must do everything we can to prevent and end atrocities in our time."The day was also marked for the first time at the Pentagon by US Defense Secretary Leon Panetta at a ceremony attended by survivors and by Defense Minister Ehud Barak, with whom Panetta had been meeting.Panetta said Barak's career as a decorated soldier and a leader was in itself a rebuke to the Nazis.Survivors helped "build a strong and vibrant Jewish state in Israel," he said. "Ehud's life has been a living tribute to the memory of the Holocaust."