Pope Benedict XVI has warned participants at the opening session of the Synod of Bishops for the Middle East of the threat of "false gods" that beset the modern world.

After leading prayers in the Synod hall, the Pope spoke off-the-cuff for about 20 minutes about the meaning of the psalms that were chanted by the 185 Synod fathers. He traced humanity's historical move away from polytheism and focused on the meaning of Christ's entry into human history.

But he said the modern world was still threatened by an array of destructive powers based on "false divinities that must be unmasked". These include the ideology of terrorism that purports to act in the name of God, drug abuse that devours human lives like a beast, as well as a widespread view of marriage that no longer values the virtue of chastity, he said.