David Freidman, U.S. President Donald Trump's pick for ambassador to Israel, plans to apologize for saying that supporters of the pro-Israel lobby J Street are "worse than kapos," referring to Jews who worked for the Nazis in concentration camps.

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The New York Times reported that representatives on behalf of Friedman told officials including Senator Benjamin Cardin (Md.), the senior democrat on the Foreign Relations Committee, that during his confirmation hearing Freidman will "express regret" for his derogatory remarks.

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The Senate panel is set to begin hearings on the appointment of Friedman, Trump's bankruptcy lawyer and a supporter of Israeli settlements' expansion who opposes the establishment of an independent Palestinians state.

J Street, a pro-Israel anti-occupation organization, is urging all those who oppose Friedman’s appointment to write their senators and encourage them to reject his nomination.

For Friedman’s appointment to be blocked, all the Senate Democrats, as well as three Republicans, would have to vote against him.

On Tuesday, more than 600 American rabbis and cantors published a letter expressing their opposition to Friedman's appointment. In their letter, the rabbis and cantors ask that either Trump withdraw the nomination, or alternatively, that the Senate reject it. The letter expresses concern about Friedman’s “denigration of American Jews who believe differently from him and his policy positions that we believe run contrary to the interests of the United States and Israel.”

The signatures were collected by a coalition of progressive organizations deeply opposed to Friedman’s appointment, including J Street, T'ruah, New Israel Fund, Ameinu, NCJW, Partners for Progressive Israel and Americans for Peace Now.

Orthodox Union, the largest U.S. Jewish Orthodox group, however urged the Senate panel on Tuesday not to view Friedman as an extremist simply because he opposes the two-state solution. The letter came short of endorsing Friedman, but defended his opposition to a two-state solution, which is to the right of the stated position of Prime Minister Benjamin Netanyahu.