A senior Austrian Cardinal who has been widely tipped in the media to be pope has warned of an "Islamic conquest of Europe" and said that the Continent is in danger of "forfeiting" its Christian heritage.

Cardinal Christoph Schönborn, the Archbishop of Vienna, is reported to have said in a speech to mark the 333rd anniversary of the Battle of Vienna: "Will there be an Islamic conquest of Europe? Many Muslims want that and say: Europe is at its end."

The Cardinal reportedly went on to pray: "God have mercy on Europe and on thy people, who are in danger of forfeiting our Christian heritage". He added that this was already being felt "not only economically, but above all, in human and religious matters".

Cardinal Schönborn, 71, is a conservative who has been referred to as the "spiritual son" of his one-time mentor, Pope Benedict XVI.

The comments came as a new study in the US found that only 14 per cent of Catholics have a favourable view of Muslims. The poll, carried out by the Bridge initiative, a multi-year research project that focuses on Islamophobia at Georgetown University, also found that Catholic media outlets present a biased view of Islam and that some 39 per cent of Fox News viewers have an unfavourable view of the religion, compared to a quarter of CNN viewers.

The poll of 1,027 self-identified Catholics found that one in three said they had either very or somewhat unfavourable views.

The report, entitled Danger & Dialogue: American Catholic Public Opinion and Portrayals of Islam, finds that nearly half of Catholics can't name any similarities between Catholicism and Islam.

An apparent bias was found among certain Catholic media outlets. More than 60 per cent of readers of outlets like the Catholic World Report and Patheos Catholic blogs said they had unfavourable views of Muslims. However, the author of the study notes that only a fraction of respondents consume Catholic media regularly.

Father Patrick Ryan of the Society of Jesus, McGinley professor of religion at Fordham University, said Catholic people tend to be "rather hostile to Muslims with perceptions coloured by things like 9/11 and the persecution of Christians in places like Syria".