Britain's leading interfaith organisation has backed a statement by the two Chief Rabbis of Israel condemning a Christian-Jewish prayer vigil due to take place at Temple Mount.

The Council of Christians and Jews said that while it was good for Christians and Jews to experience each other's worship traditions, the two religions were separate and joint services were not possible.

The Chief Rabbis fear that the event has too much of a "messianic" content and suspect an agenda aimed at proselytism. This combined with a mixed-faith audience puts it at risk of undermining both faiths, they believe. They urged Jewish believers not to attend.

According to the Haaretz news site, their opposition is part of a larger campaign against cooperating with evangelical Christians.

The International Christian Embassy in Jerusalem, which brings together pro-Israel evangelicals from the US, has organised the event, due to take place during the Jewish festival of Sukkot in October. The Christian Embassy holds its own annual celebration of the festival, also known as the Feast of the Tabernacles.

Ashkenazi Chief Rabbi David Lau and Sephardi Chief Rabbi Yitzhak Yosef told Orthodox Jews in Israel they should not accept the invitation to attend.

They said: "To our brethren of the House of Israel we will say: Do not join this assembly, whose purpose is to prevent the true redemption of Israel. According to our holy Torah, we must keep away from this event, and it is forbidden to join them in any way."

They called on the Jerusalem city authorities to revoke the permit for the event, due to be at Hulda Gate, at the southern wall.

"It's true that one cannot prevent the believers of any faith from praying according to their religion. However, in the case of a ceremony which aims to mix between religions in a way that harms the believers of the other religion, it must not be allowed to take place," they added.

"The mutual respect between the faiths must be preserved in a way that causes no harm to one religion or the other. And in this case that balance does not exist."

Other prominent rabbis in the Old City are also quoted on posters around Jerusalem condemning the proposed vigil as a deception with a missionary agenda.

Temple Mount is the holiest site in Judaism which the devout turn towards in prayer. It is believed to be the place of the "Holy of Holies", where in ancient biblical times the high priests of Judaism received the word of God. It is also holy to Islam, being the site of the Dome of the Rock and the Al-Aqsa mosque. It is revered by Christians also because of its Jewish history.

A spokesman for the Council of Chrisians and Jews told Christian Today: "While the organisers of the event, if it is indeed a joint prayer event, may believe they have the best interests of the Jewish people at heart, they are mistaken. As the Chief Rabbinate have pointed out, Christianity and Judaism today are quite separate traditions and any sort of event which blurs the distinctions does a disservice to both. CCJ is in favour of each experiencing the worship of the other, but joint worship is not possible, unfortunately."

However, Dr Jonathan Romain, Rabbi of Maidenhead and a leading expert on Christian-Jewish relations, took a different view. He said: "There is nothing wrong with religious leaders telling their own followers that it is better not to participate in a particular event, but everything wrong in trying to ban the ceremonies of other faith groups. Religious freedom means allowing people to worship God in whatever way they see fit, providing it causes no harm, and leaving it up to God whether to listen to their prayers or not."

The International Christian Embassy in its description of the event makes no mention of Jewish participation, the Times of Israel reports, but states that as part of a week-long tour in honour of the Feast of Tabernacles, "we devote our final morning to seeking the Lord together in prayer for our families, churches, and nations, as well as for Israel and the Middle East region. Respected ministers from around the world will lead us in prayer, and a time will also be set aside for prayer for the sick and body ministry."