European rabbis have waded into a dispute that threatens to fracture American Orthodoxy.

The Conference of European Rabbis (CER) voted last week to blackball graduates of a New York yeshivah at the centre of a row over its modernising tendencies.

The CER said that it would not recognise as rabbis graduates of Yeshivat Chovevei Torah (YCT) in New York, because it had deviated from the "basic tenets of Jewish faith".

According to a spokesman, Chief Rabbi Ephraim Mirvis - an associate president of the CER - "does not disagree with the substance of the resolution, which relates to the origins of Jewish law as being in the revelation at Sinai. But he is of the view that positive reinforcement of traditional Orthodox values and practices is a better way of making the point".

The CER move reflects increasing alarm at the growth of Open Orthodoxy, a loose grouping of American rabbis inspired by Rabbi Avi Weiss of Riverdale.

Rabbi Weiss founded YCT in 1999 to promote a more modern ethos than existing Orthodox academies in the USA. He also co-founded Yeshivat Maharat in New York, which controversially ordains Orthodox women as clergy.

In recent weeks, Open Orthodoxy has been denounced as heretical by the strictly Orthodox Agudath Israel of America, while the central Orthodox Rabbinical Council of America issued a fresh attack on Yeshivat Maharat.

The CER declared that it would accept only rabbis who "lead their communities according to Jewish traditions as derived from Mount Sinai" and would not recognise rabbis who acted
according to the principles of Open Orthodoxy.

The Chief Rabbi of Finland, Simon Livson, is a graduate of YCT, as is Rabbi Benjamin Elton, one of two British alumni from the UK, who was recently appointed senior rabbi of the Great Synagogue in Sydney, Australia.

CER president Rabbi Goldschmidt explained that the "main problem" for his colleagues at the moment was not women's ordination but theological belief.

"The major issue we are concerned about, is that some teachers in the rabbinical school of Open Orthodoxy have doubted some of the 13 principles of Maimonides - among them, the divine origins of the Torah," he said.

If rabbis seeking pulpits in Europe did not subscribe to Maimonides's Thirteen Principles of Faith, Rabbi Goldschmidt said, "we are not going to accept it".

But YCT president Rabbi Asher Lopatin, rejected the accusations, saying that all its rabbis and students were "fully committed to Orthodoxy and to all the 13 principles of the Rambam [Maimonides]".

Two years ago, a YCT graduate, Rabbi Zev Farber, stirred controversy in Orthodox circles when he argued that the Torah was an edited document and that rabbis should take into account academic scholarship on the Bible.

But Rabbi Lopatin said that Rabbi Farber had not taught at YCT "as far as I know".

Rabbi Elton said that both Chief Rabbi Mirvis and the London Beth Din "regard my semichah [ordination] as valid and would not object if I took a rabbinic post in Britain, and Chief Rabbi Mirvis wrote a warm letter to my congregation on my appointment." Describing the CER resolution as sad, he said: "I imagine that the CER has been misled by some very shrill voices in the US."