By David Willey
BBC News, Rome
A number of Catholic cardinals have warned Italian women against mixed marriages with the rising number of Muslims in the country.
Italian women have been warned of cultural differences
Church officials say that as Italy's Muslim population touches the one million mark, some 20,000 mixed marriages took place this year alone.
That is an increase of around 10% on last year.
The Catholic Church's official position is to encourage dialogue between Rome and other religions, including Islam.
The late Pope John Paul II was the first pope in history to pray in a mosque, when he visited Damascus. His successor, Benedict XVI, has insisted that he is also keen to promote religious and cultural dialogue with the Islamic world.
But two documents published in Rome have called for extreme caution by Catholic women contemplating marriage to a Muslim.
In one, issued by the Vatican last year, a Vatican cardinal, Stephen Hamao, wrote about what he called the "bitter experiences" that European women have had in marrying Muslims.
Pope John Paul II had tried to improve relations between faiths
The difficulties are compounded if the couple then goes to live in a Muslim country, the cardinal warned.
The tone was unusually strong in an age when interfaith dialogue seems the predominant buzz word. Then last month, Cardinal Ruini, the head of the Italian bishops, added his voice.
In addition to the problems any couple faces setting up a family, he said, Catholics marrying Muslims have to reckon with extra difficulties arising from deep cultural differences.
Some Muslim scholars have expressed surprise at the Vatican documents and Italian liberal groups have also criticised them.