"Following World War II they resorted to military aggressions to make an entire nation homeless under the pretext of Jewish suffering," Ahmadinejad told the conference, speaking through a translator.
"And they sent migrants from Europe, the United States and other parts of the world in order to establish a totally racist government in the occupied Palestine," he said.
"And in fact, in compensation for the dire consequences of racism in Europe, they helped bring to power the most cruel and repressive racist regime in Palestine."
British ambassador Peter Gooderham condemned the Iranian leader's "offensive and inflammatory comments" that prompted the temporary walk-out. Delegates said they would return after he had finished speaking.
"Such outrageous anti-Semitic remarks should have no place in a U.N. anti-racism forum," he said.
Slovenian ambassador Andrej Logar called the Iranian comments — which prompted applause among delegations that remained in the U.N. assembly hall — "detrimental to the dignity of this conference."
"The word Zionism personifies racism that falsely resorts to religion and abuses religious sentiments to hide their hatred and ugly faces," Ahmadinejad told the conference.
The United States is among eight Western powers who are boycotting the week-long conference because of fears it will be used as a platform for unfair criticism of Israel.
"We strongly deplore the language used by the president of Iran. In our view this speech was completely inappropriate at a conference designed to nurture diversity and tolerance," said Rupert Colville, spokesman for Navi Pillay, U.N. High Commissioner for Human Rights, in a statement.
Norwegian Foreign Minister Jonas Gahr Store told the conference after Ahmadinejad had finished speaking that his words amounted to incitement to hatred, and through his words Iran had made itself the odd man out at the meeting by undermining the agreement so far on the conference declaration.
"Norway will not accept that the odd man out hijacks the collective efforts of the many," he said.
(Reporting by Robert Evans and Jonathan Lynn; Writing by Laura MacInnis; Editing by Dominic Evans)
