Geneva - US attorney Alan Dershowitz said on Monday on the sidelines of the Durban Review Conference on racism in Geneva that Switzerland's president was supportive of "hate mongering" and that the anti-apartheid activist Desmond Tutu was a "racist and bigot".
He said he would urge the administration of US President Barack Obama to cease using Switzerland's services as its representative in Iran.
The US and Tehran have not had diplomatic relations since the Islamic revolution in Iran and the subsequent hostage taking at the embassy there.
Swiss President Hans Rudolph Mertz met Sunday with the Iranian President Mahmoud Ahmedinejad, who later in a speech before the conference was derisive of Israel.
"Tutu is a bigot and a racist," said Derschowitz about the Nobel Peace Prize winning South African archbishop. He is "blind, deaf and dumb when it comes to issues of Israel".
Tutu has voiced support for the Palestinians and headed a fact finding mission to the Gaza Strip for the UN's human rights bodies.
The lawyer, who has defended OJ Simpson and written books backing Israeli military policy in the Palestinian territories, said that Norway was "one of the biggest offenders against Israel."
Norwegian Foreign Minister Jonas Gahr Store followed Ahmedenjad at the conference and condemned the Iranian leader's speech but stayed on at the event.
European Union delegates walked out of the plenary in middle of the Iranian leader's speech.
Dershowitz called the Durban review a "conference of hate".
Nobel Peace Prize winner Elie Wiesel said the Iranian president should "be arrested and charged with incitement for genocide, which is a crime against humanity".
Ahmedinejad's "place is not in the UN, his place is in an international court", said Wiesel, a Holocaust survivor. - Sapa-dpa