Prince Charles has said Muslim leaders must warn their followers about the "indescribable tragedy" of the persecution of Christians in the Middle East.
The heir to the throne has recorded a video message insisting that faith leaders do not remain "silent" over a lack of respect between traditions.
His comments accompany the publication of a new report which concludes that Christians are the "most persecuted religious minority" in the world.
The report, by a Roman Catholic charity, said Muslim countries dominate the list of places where religious freedom is under threat.
It argues that extremism has contributed to a decline in religious freedom in the UK and singles out the corrosive influence of Islamic State (IS).
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IS fighters pushed Christians out of Mosul, in northern Iraq, in July - ending a presence that began in the early years of Christianity. Shia Muslims and religious minorities have also been targeted by the Sunni Islamist group.
The report by Aid To The Church In Need also highlights the kidnapping of 200 Christian schoolgirls by the Islamist terror group Boko Haram in Nigeria.
In his video message, Charles said: "It is an indescribable tragedy that Christianity is now under such threat in the Middle East - an area where Christians have lived for 2,000 years, and across which Islam spread in 700AD, with people of different faiths living together peaceably for centuries.
"It seems to me that our future as a free society - both here in Britain and throughout the world - depends on recognising the crucial role played by people of faith.
"And, of course, religious faith is all the more convincing to those outside the faith when it is expressed with humility and compassion, giving space to others, whatever their beliefs."
Outlining his own suggestions to improve the situation, he said: "First and foremost, rather than remaining silent, faith leaders have, it seems to me, a responsibility to ensure that people within their own tradition respect people from other faith traditions.
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"We have yet to see the full potential of faith communities working together."
The report concludes that Christians are suffering the most widespread persecution but also points out that Muslims are coming under "serious" threat.
Charles said he did not want to be seen as Defender of the Faith, the title held by each monarch since Henry VIII, but as Defender of Faith in general.
But he maintained that this conviction was rooted in his own Christian faith.
"My own Christian faith has enabled me to speak to, and to listen to, people from other traditions, including Islam," he said.
Sky's Ashish Joshi said: "The Prince of Wales is no stranger to controversy - this is a highly unusual intervention.
"To record this video for the Roman Catholic charity (...) that will obviously be received as highly controversial in some areas, in some quarters."
The Prince's comments came amid news that a Christian couple had been beaten to death in Pakistan after being accused of desecrating the Koran.
The report, launched in the House of Lords, suggested that the last two years had seen a serious decline in religious freedom in many parts of the world.
As well as the persecution of Christians, it also focuses on the plight of Muslim minorities in Iraq and elsewhere in the Middle East as well as Asia.
In particular, it highlights the case of the Rohingya group in Burma, facing official restrictions on the number of children families are allowed.
