US President Barack Obama has condemned Israeli settlement building - and admitted US foreign policy has been wrong in the past.
During a speech at Al-Azhar university in Cairo, he told the Israeli government that continuing to construct new Jewish homes in the occupied Palestinian territories must stop immediately.
And he went further than any US President in recent memory by conceding that US policies towards Iran and in its reactions after the 911 terror atrocity had been mistaken. He also implied that the invasion of Iraq had been a mistake.
Mr Obama flew to Cairo on Thursday after staying overnight at the farm of King Abdullah of Saudi Arabia outside the capital Riyadh.
He also made thinly-veiled criticisms of the Middle Eastern countries to which America has in the past appeared uncritical.
But his toughest words, and one of the most warmly received sections of the speech, were his rebuke for Israeli PM Binyamin Netanyahu, who has refused to halt West Bank settlement expansion.
"The United States does not accept the legitimacy of continued Israeli settlements," he said.
"This construction violates previous agreements and undermines efforts to achieve peace. It is time for these settlements to stop."
He added that the US bond with Israel, the source of much Arab distrust of the United States, was unbreakable, and he rejected "baseless, ignorant and hateful" rants by those who deny the Nazi Holocaust.
He also voiced compassion for the millions of Palestinians who have lived for decades under Israeli occupation in refugee camps in Gaza and the West Bank, and called on all parties to play their part in reviving stalled peace talks.
"Let there be no doubt: the situation for the Palestinian people is intolerable," he said.
"The only resolution is for the aspirations of both sides to be met through two states, where Israelis and Palestinians each live in peace and security. That is in Israel’s interest, Palestine’s interest, America’s interest, and the world’s interest."
He later visited the Buchenwald concentration camp his great-uncle helped to liberate, laid a white rose at a memorial to its victims, and described the site where 56,000 people died as the "ultimate rebuke" to Holocaust deniers.
After seeing the crematoriums, guard towers and barbed-wire fences, and a clock set at 3:15 – when the camp was liberated on 11 April 1945 – he said: "These sites have not lost their horror. More than half a century later, our grief and our outrage have not diminished."