Malcolm Hoenlein, vice president of the Conference of Presidents of Major American Jewish Organisations, has asked for an apology from the African Union (AU) after Egyptian and South African delegates to a summit said they would not participate until the "Israelis" left.
Mr Hoenlein's delegation - made up of US Jews, not Israelis - had been invited to the summit in Equatorial Guinea to facilitate ties between African leaders and Israel and the Jewish diaspora. They left the event two hours early.
It was the first time a Jewish delegation had been invited to an AU summit.
Before the opening ceremony, his group had some "amazing meetings", Mr Hoenlein said.
Many of the people they spoke to, he said, "boasted about their ties to Israel" and were "very open to working with Jews".
Topics discussed included the disappearance of three Israeli teenagers, the rise of Islamist extremism in Africa and economic and agricultural issues, he said.
"Given its relationship with Israel, it was surprising that Egypt acted in such an offensive way," he added.