Obama pays homage at symbolic Israeli sites on last day of visit

US President Barack Obama visited Israel's most powerful national symbols, paying homage at the Holocaust memorial and the graves of the founder of modern Zionism and assassinated prime minister Yitzhak Rabin.

The image of Obama crouching in reflection after laying a wreath in the Yad Vashem memorial to the six million Jews killed by Nazis added another emotional layer to a three-day trip full of symbolic gestures and appeals for peace.

Wearing a Jewish skullcap, Obama rekindled an eternal flame next to a stone slab above ashes recovered from extermination camps after World War Two.

"We have a choice to acquiesce to evil or make real our solemn vow - never again," Obama said.

Earlier, in accordance with Jewish tradition, he placed stones on the graves of Theodor Herzl, the Zionist visionary who died more than four decades before the 1948 founding of Israel, and Rabin, who was shot dead in 1995 by a Jewish gunman opposed to his peace moves with the Palestinians.

Officials said the visit to Yad Vashem and the Mount Herzl cemetery in Jerusalem was aimed at correcting an impression the president had given in a speech in Cairo in 2009, where he appeared to argue that the legitimacy of the Jewish state stemmed from the Holocaust.

At Yad Vashem, Obama made clear he recognised that Jewish roots to the Holy Land were centuries-old.

"Here on your ancient land, let it be said for all the world to hear, the state of Israel does not exist because of the Holocaust, but with the survival of a strong Jewish state of Israel, such a Holocaust will never happen again," he said.

Obama was due to fly later in the day to Jordan for talks with King Abdullah, a US ally, about an array of problems, including the civil war in neighbouring Syria and stalled Israeli-Palestinian peace moves.