Kadima MK Nachman Shai ripped into the Israeli embassy here Wednesday for shunning J Street, warning that it was a mistake that would alienate an important part of the American Jewish community. Shai told The Jerusalem Post that he had sent a letter questioning the embassy's policy on J Street to Foreign Minister Avigdor Lieberman and that he plans to raise the issue when Lieberman or his deputy appear before a plenary session of the Knesset. "This is a grave mistake by the embassy," Shai said, responding to recent comments published in the Post, in which the embassy said that J Street supports policies that could "impair Israel's interests." He also urged Ambassador Michael Oren to attend the self-described "pro-Israel, pro-peace" lobby's first annual conference later this month. "It serves the entire Jewish people," Shai said of the embassy. "We have to build a relationship with the Jewish community in America [and] every segment of this community is entitled to have a role in the relationship with Israel." Shai served as the director-general of the United Jewish Communities Israel, the umbrella organization for America's Jewish federations, before becoming a member of Knesset in the centrist opposition party. He also once served in Israel's Washington embassy. Though Shai noted J Street disagreed with several key Israeli policies, he said they sought to aid Israel, not to delegitimize it, and that they crossed no "red lines." As such, Shai advocated that the Israeli government take a position of "bringing them in, talking to them, trying to convince them." Doing otherwise, he warned, mean "we'll lose some of them," and that, "We'll push them a little bit out of the close circle of friends. It will just make them angry." The new progressive Jewish group has ruffled feathers by taking several positions at odds with the Israeli government in recent months, including arguing against the immediate imposition of additional sanctions on Iran, even as Israel pushes for greater action, and backing US President Barack Obama's call for a complete settlement freeze in the face of Israeli opposition. J Street has stressed, though, that it is supportive of Israel and believes its positions will best help ensure the Jewish state's survival. Embassy spokesman Jonathan Peled declined to comment on Shai's charges since he hadn't seen the MK's letter to the foreign minister, noting that any response would most probably be conveyed to Shai personally. He noted that Oren hadn't yet decided whether he would be attending the conference, despite J Street's reiteration of its long-standing invitation in an open letter published in Wednesday's Post. "We received the letter. We are reviewing it, and a decision on the embassy's participation will be made known in due course," Peled said. J Street spokeswoman Amy Spitalnick also declined to comment, except to say that, "We still hope the ambassador will choose to participate in the conference."