On the eve of his trip to Iraq, Pope Francis paid tribute on Thursday to those who have suffered from years of violence, saying he came as a "pilgrim of peace".

In a video message, the 84-year-old offered his hand to "brothers and sisters of other religions", but also highlighted the heavy toll paid by Iraq's Christian communities, saying there had been "too many martyrs".

"I long to meet you, to see your faces, to visit your land, ancient and extraordinary cradle of civilisation," the pope said, the day before his three-day trip.

"I come as a pilgrim, a penitent pilgrim to implore forgiveness and reconciliation from the Lord after years of war and terrorism.

"I come as a pilgrim of peace in search of fraternity, animated by the desire to pray together and to walk together, also with the brothers and sisters of other religions."

There had been "too many martyrs", he said, while survivors "have in your eyes the images of destroyed houses and desecrated churches, and in your hearts the wounds of loved ones left behind and homes abandoned".

Francis is fulfilling the dream of a predecessor, John Paul II, by visiting Iraq -- despite a rampaging coronavirus epidemic and an upsurge in violence. 

The country's Christian community -- one of the world's oldest -- has fallen from 1.5 million in 2003 to just 400,000 today.