“Jewish history compels us to take exceptional caution on these matters and forbids any harming of the other, the guest and the foreigner.”

This was the surprising denunciation made on Monday morning by the Foreign Ministry, following an arson attack on a flat rented to four African immigrants on Jerusalem’s Jaffa Road.

Surprising because, in the past, the ministry has not been involved in the question of the treatment of the thousands of illegal African immigrants who have crossed over the Sinai border, looking for shelter and work in Israel.

The ministry’s unprecedented statement followed an even sterner denunciation by Foreign Minister Avigdor Lieberman who said in a speech in Eilat, where many of the immigrants have found work, that ”the Foreign Ministry is making huge efforts to reach agreements with their countries of origin, and every interview and bombastic statement by Knesset members and ministers pushes us back six months.”

Mr Lieberman did not mention his cabinet colleague, Shas leader and Interior Minister Eli Yishai, but the direction of his remarks was unmistakable.

In recent months, Mr Yishai has been waging a war of words against the influx of immigrants, blaming them for spreading disease and crime, and blaming the NGOs that support their rights, for eroding the Jewish character of the state.

Last week, he threatened to fine any local council that employed illegal immigrants and this week he published plans to begin mass deportations.

Mr Lieberman’s contribution is surprising; only a few weeks ago he proposed a deportation plan of his own, and he has never been known as an advocate for migrant workers’ rights.

But he is constantly mapping out the electoral terrain, searching for the hot-button issues that will galvanise his constituency.

Although Mr Lieberman’s party, Yisrael Beiteinu, has sat relatively harmoniously in coalitions with Shas, when it gets towards election-time, the Charedi party’s hold on the Interior Ministry is a perennial target of Yisrael Beiteinu propaganda.

The party’s mainly Russian-born voters are well aware of the travails of immigration to Israel, especially the difficulties faced by non-Jews trying to find their footing in its society.

Mr Lieberman seems to think that his potential voters may have some sympathy with the African immigrants.

Shas and a large number of Likud MKs have given support to the protests against the African presence in south Tel Aviv, and Prime Minister Benjamin Netanyahu announced this week that 25,000 illegal immigrants could be deported immediately.

Mr Lieberman has identified an issue here on which he can make a principled stand, setting himself apart from his coalition partners.

Recent research shows that a growing proportion of the younger “Russian” generation in Israel is not happy with their community’s non-democratic, illiberal image. Avigdor Lieberman is trying to woo them back.