Religious Israelis are more concerned than their secular counterparts about the potential danger of assimilation presented by the influx of non-Jewish immigrants from the Former Soviet Union to Israel, according to a survey released Wednesday by the Immigration and Absorption Ministry. Some 87 percent of religious Israelis said they were concerned about intermarriage and assimilation in the wake of the arrival of approximately 300,000 non-Jewish FSU immigrants, who came to Israel under the Law of Return. The criteria for determining automatic Israeli citizenship under the Law of Return are more inclusive than the Orthodox definition of Jewishness. Therefore, immigrants whose father or paternal grandparents are Jewish are eligible for citizenship, but not considered Jewish according to Halacha. The Absorption Ministry survey, based on a sample of 700 Israelis aged 18 or older, was released ahead of Shavuot, a holiday with strong motifs of conversion - including the biblical story of Ruth the Moabite and the "conversion" of the Jewish people on the Mount of Sinai when they received the Torah. In a related incident, several Jewish organizations will protest on Thursday in front the Rabbinical Courts' headquarters what they call the mistreatment of converts by the Chief Rabbinate. Ne'emanei Torah VeAvodah, ITIM, Kolech, Mavoi Satum, and The Center for Women's Justice, will all call on Chief Rabbi Shlomo Amar to repudiate a High Rabbinical Court decision from last month that cast doubt on the Jewishness of thousands of converts to Judaism. Court Judge Rabbi Avraham Sherman claimed in the decision that most non-Jewish immigrants who converted to Judaism under the auspices of the National Conversion Authority had no intention of accepting an Orthodox way of life, and therefore should not be considered Jewish. Marriages and divorces are controlled by the Orthodox Chief Rabbinate: Rabbis who accept the High Rabbinical Court's decision will not permit these converts to marry Jewish Israelis. In cases where these converts are already married to a Jew the marriage would be considered null and void and the woman might not be eligible for benefits such as alimony and child support from her ex-husband. Chief Sephardi Rabbi Shlomo Amar, who is the ultimate state-recognized halachic authority for conversions, has diplomatically avoided making an unequivocal statement on the matter, fearing a backlash from more ultra-Orthodox rabbinical authorities. Yonatan Ben-Harosh, a spokesman for Ne'emanei Torah Ve'Avodah, said that the main objective of the demonstration was to force the Chief Rabbi to come out in defense of the converts and to assure them all that their conversions would be recognized for marriage and divorce purposes. Meanwhile, haredi rabbinical authorities are putting pressure on Amar to back the High Rabbinical Court's scrutiny of the conversion authority. The ultra-Orthodox Edah Haredit, a rabbinical organization that brings together Hassidic sects such as Satmar and the more insular Lithuanian streams, issued a statement calling to immediately halt all conversions performed by the Conversion Authority. The rabbis also called not to recognize as Jews those who were converted by the authority. "We call on all rabbis who deal with marriages not to allow converts who did not accept upon themselves the yoke of the commandments to marry Jews," wrote rabbis Tuvia Weiss, Moshe Sturnbach and others who sit on the Edah Haredit's rabbinical court. "These converts are a stumbling block to the Jewish people." According to the Absorption Ministry's survey, 74% of secular Israelis said that non-Jewish immigrants should be allowed to convert without accepting an Orthodox lifestyle. Some 45% of religious agreed.