Vatican City (AFP) - A top African cardinal has described the threat posed by Islamic extremism and western liberal culture as the twin "Beasts of the Apocalypse" comparable to Nazism and communism.

"Theological discernment allows to see in our times two unexpected threats -- almost like the Beasts of the Apocalypse -- from two opposite positions: on one side the idolatry of western freedom, on the other religious fanaticism,"

Sarah reportedly said the secular western world's way of thinking threatened to destroy the family through "quickie divorces, abortion, homosexual unions: look at gender theory, Femen (a feminist group known for topless protests), the LBGT lobby.

"On the other side, there is the pseudo-family of an ideological Islam which legitimises polygamy, sexual slavery, child marriage: look at Al-Qaeda, IS, Boko Haram.

"Certain keys allow us to discern the same demonic origin of these two movements: they both advocate a universal and totalitarian law, they're both violently intolerant, destroyers of families and the Church, and openly anti-Christian."