Three Israelis from a far-right group were charged on Monday with setting fire to a classroom in an Arab-Jewish school that has been a symbol of co-existence in Jerusalem.

Israel’s Shin Bet security service said brothers Nahman and Shlomo Twito, aged 18 and 20, and Yitzhak Gabai, 22, belong to Lehava, a group that objects to personal or business relations between Jews and Arabs.

According to the indictment, the men set fire to a classroom in the Hand-in-Hand school last month and sprayed anti-Arab graffiti on the walls of its courtyard. Classes were not in session at the time.

The brothers, who live in a settlement in the occupied West Bank, and Gabai, a resident of Jerusalem, were led into court handcuffed and smiling. They made no comment and were not asked to enter a plea.

More than 600 pupils from pre-school through high school attend Hand-in-Hand. Its student population is divided equally between Israelis and Palestinians, with lessons given in both Arabic and Hebrew.

The Shin Bet said Lehava teaches the ideology of the late Meir Kahane, a far-right, U.S.-born rabbi who won election to the Israeli parliament in 1984 and advocated the expulsion of Palestinians from Israel and the occupied territories.

Labeled racist and undemocratic by Israel, Kahane’s group, Kach, was banned from politics in 1988. Two years later, Kahane was assassinated in New York by an Egyptian-American gunman.

Violence in Israel and the Palestinian Territories has surged in the past few months. Attacks carried out by Palestinians have killed 11 Israelis, and 12 Palestinians have been killed, including several of the assailants.

Last week a Palestinian minister died after a confrontation with Israeli border police in the occupied West Bank. In July, a Palestinian youth was burned to death by Jewish attackers. Three Israeli teens were killed by Palestinian militants in the West Bank in June.