Famed Israeli author Amos Oz slammed AIPAC during his opening remarks at the J Street annual conference in Washington, DC, on Saturday night, calling the pro-Israel lobby group “militant” and “extremist.”

Oz was quoted in New Voices as saying,”Let us all be united, but why unite under the militant, hawkish, extremist manner of AIPAC?… There is more than just one way to be a good Jew. There is more than just one way to be a good Zionist.”

Oz was joined by fellow Israelis Stav Shaffir, a social protest leader, and Yeruham mayor Michael Biton in opening the J Street Making History conference, which runs from March 24-27 in Washington DC. The left-leaning Jewish advocacy group was formed in 2008 as a counter to AIPAC.

Over 2,500 people are expected to attend the conference, including over 600 college students from 125 universities in five countries, according to New Voices.

Other Israeli participants include former prime minister Ehud Olmert, MKs Avishay Braverman, Raleb Majadle and Zahava Gal-On, and retired general and former Haifa mayor Amram Mitzna. The Israeli Embassy in Washington, which has in the past boycotted the conference or sent an observer, is this year sending deputy ambassador Baruch Binah as an official representative.

Valerie Jarrett, a top adviser to US President Barack Obama, will also address the J Street conference. She will join Tony Blinken, the national security adviser to Vice President Joe Biden, in a session on Monday on the US role in advancing Middle East peace.

Jeremy Ben-Ami, the group’s director, had complained in an interview with Jeffrey Goldberg of the Atlantic that sending Blinken signaled that the administration feared sending a higher-ranking official to the liberal pro-Israel group’s conference, and that it was succumbing to pressure from some centrist and right-wing groups to isolate the lobby.

“This decision is really indicative of the problem we started J Street to fix,” Ben-Ami said. “This is precisely the kind of calculation that shouldn’t be made.”

But in an interview with the Times of Israel, Ben-Ami said that “this level of representation by the Administration is a strong re-affirmation of its support for the role that J Street plays in representing many Jewish Americans in the debates over Israel in the political and policy worlds.”

In a statement Friday announcing Jarrett’s participation, Ben-Ami said that along with a video message from Israeli President Shimon Peres and a first-time participation by an Israeli diplomat, Jarrett’s attendance was a sign that J Street has arrived.

“I think it’s clear that J Street has established itself as a permanent and important part of the mainstream American dialogue on Israel,” he said.

“In our early years J Street’s challenge was to prove that one could be both pro-Israel and pro-peace,” he continued. “Now our challenge is to lead the pro-Israel movement into the future under the only banner that can give Israel security as the democratic, Jewish homeland: Bold action in support of a two-state solution.”

In his interview with the Atlantic, Ben-Ami also said that J Street would next year apply for membership in the Conference of Presidents of Major American Jewish Organizations.