"We must not generalise about an entire public due to a small and violent minority," Prime Minister Benjamin Netanyahu said following Ashkelon mayor Itamar Shimoni's announcement barring Arab construction workers from projects in his city's kindergartens.
"There can be no discrimination against Arab Israelis," Netanyahu said in a statement, stressing the "full equality before the law of every citizen regardless of religion, race or sex."
Shimoni wrote on his Facebook page on Wednesday that he was freezing "until further notice" a programme to build bomb shelters for kindergartens in the southern coastal city on which Arab workers were employed.
The statement did not make it clear whether he was referring to Arab citizens of Israel or to Palestinian workers, but in remarks quoted by Haaretz newspaper he appeared to be speaking of Israelis.
"I have nothing against Israeli Arabs, they work with us throughout the year and do construction for us," he told the paper.
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In addition, he wrote on Facebook, "I have instructed that armed guards be posted at all kindergartens adjacent to building sites where Arab workers are employed."
The move comes at a time of growing tension between Jews and Arabs after weeks of clashes in Jerusalem and elsewhere and the killing Tuesday of four worshippers at a Jerusalem synagogue and a policeman by two Palestinians from annexed east Jerusalem.
At such a time, Shimoni told Haaretz, "I think it is wrong to allow Arab workers into the kindergartens."
Israel has 1.7 million Arabs -- Muslims and Christians -- representing 20.7 percent of the population.
They are descendants of the 160,000 Palestinians who remained on their land after the creation of the Jewish state in 1948.
Sawsan Zaher, a lawyer with Israeli NGO Adalah, which works for Arab rights, told AFP the Ashkelon edict was "a racist, discriminatory and illegal decision to ban a worker for something that has nothing to do with their work and only for their national or religious affiliation."
Justice Minister Tzipi Livni, leader of the centrist HaTnuah party, told public radio the order was "not only ugly but illegal."