A United Nations official who has been the subject of repeated complaints provoked fresh outrage this week over comments viewed as linking the Boston bombings with US policy on Israel.
Richard Falk, the UN's special rapporteur on human rights in the Palestinian territories, who is Jewish, made his remarks in a blog on the "marathon murders".
He wrote that "the American global domination project" was "bound to generate all kinds of resistance in the post-colonial world. In some respects the United States has been fortunate not to experience worse blowbacks, and these may yet happen, especially if there is no disposition to rethink US relations to others in the world, starting with the Middle East."
He also claimed that "as long as Tel Aviv has the compliant ear of the American political establishment, those who wish for peace and justice in the world should not rest easy".
The United States ambassador to the UN, Susan Rice, said she was outraged by his "highly offensive" comments. "Someone who spews such vitriol has no place at the UN," she added. "Past time for him to go."
David Harris, executive director of the American Jewish Committee, said that "his malicious propaganda regarding the US and Israel has no place in any international body that takes itself and its mission seriously." The World Jewish Congress and United Nations Watch also called for his dismissal.
Abe Foxman, national director of the Anti-Defamation League, said that it was "outrageous that the UN human rights council continues to support such a wildly conspiratorial and highly biased extremist as a reliable 'expert'.
But Mr Falk, in response to a question from the JC, denied making any link between the Boston attack and Israel. "My reflections were only a commentary on focusing all attention on the wrongdoing of the perpetrators, and avoiding self-scrutiny as to why the United States, more than elsewhere, was the target of such extremist behaviour," he explained.
At the end of last year Mr Falk was condemned by UK Prime Minister David Cameron for publishing on his blog an Arab cartoon showing a dog with a kipah urinating on a figure of justice.
Meanwhile, one of the suspected Boston bombers, Tamerlan Tsarnaev, who was killed by police, had sought a copy of the antisemitic book Protocols of the Elders of Zion, according to the Forward newspaper.