Education Secretary Michael Gove is exploring how to regulate weekend religious schools as evidence emerged this week that antisemitic material is being taught in Saudi-linked classes in the UK.
Children are being asked to list the "reprehensible qualities" of Jews in a network of more than 40 supplementary schools, according to an edition of BBC1's Panorama broadcast on Monday.
They learn that Jews are "cursed by God" and look like "monkeys and pigs" from textbooks published by Saudi Arabia's Ministry of Education.
Fifteen-year-olds are also being told that "Zionists want to establish world domination for Jews by inciting world conflict".
Panorama reporter John Ware said that the network - which serves 5,000 children - was linked to the Saudi Embassy in the UK, although the embassy was quoted saying that it had "nothing to do with" what was taught.
Koran scholar Professor Neal Robinson said that the material could provide "ammunition for antisemitism".
Mr Gove told the programme: "I'm clear that we can't have antisemitic material of any kind being used in English schools."
He said that he was awaiting a report from the inspection service Ofsted on how to keep a closer eye on part-time educational institutions.
Jon Benjamin, chief executive of the Board of Deputies, commented after the programme: "A system that allows schools to operate in this way needs to look again at how abuses of this nature can be detected and addressed."
Mark Gardner, communications director of the Community Security Trust, said: "This adds to growing evidence about the teaching of antisemitism and other unacceptable or offensive views in some Muslim schools. We will be encouraging the relevant authorities to ensure that appropriate measures are taken to combat this challenging problem."
In a statement, the Saudi Embassy said it was "investigating what was said on the programme to ensure that our commitment to the respect of other faiths is upheld". But it insisted that it "does not and has not authorised the use of any discriminatory or objectionable educational materials".
It claimed that Panorama had "inappropriately involved itself in the
dangers of selectively quoting from texts written centuries ago outside of their historical, cultural and linguistic context".
Maajid Naawaz, director of the anti-extremist think tank, the Quilliam Foundation, pointed out on the Harry's Place website: "It would be easy, but mistaken, to accuse the Saudis of funding this fanaticism, as the teaching is based on their old textbooks. But the Saudis have moved on, albeit very slowly, in a positive direction, ditching those textbooks on the way."