Pope Francis sent a message to Iraqi Christians last weekend in a display of solidarity for the persecuted community there.

The Islamic State (IS) has killed and exiled thousands of religious minorities from Iraq and Syria, but the Pope encouraged the persecuted to stand firm in their faith.

The Pope recounted St Therese of Lisieux's comparison of herself and the Catholic Church to a sturdy reed being battered in a storm.

"You are, in this moment, this reed," the Pope said in a videotaped message. "You bend with pain, but you have the strength to carry your faith forward.

"You are God's reeds today! The reeds which bend over in this ferocious wind, but then rise up!"

There have been Christians in Iraq for 2,000 years, and there were as many as 1.5 million Iraqi Christians before the United States invaded the country in 2003. Current estimates put the number of Christians living in the country at 200,000 but that number is dropping as thousands flee the wanton violence.

IS controls the Iraqi cities of Mosul, Baiji, and Fallujah, as well as parts of Syria, and is seeking to establish a Sunni Muslim state across the countries. Churches and Shiite shrines have been bombed, and homes and historically significant sites destroyed.

"It would seem that they do not want there to be any Christians, but you bear witness to Christ," Pope Francis continued. "I think of the wounds, of the pain of women with their children, the elderly and the displaced, the wounds of those who are victims of every type of violence.

"Even holy buildings, monuments, religious symbols and cultural heritage have been affected by the violence, almost as if to cancel every trace, every memory of the other," he continued.

"[Due] to an extremist and fundamentalist group, entire communities, especially – but not only – Christians and Yazidi, have suffered and continue to suffer inhuman violence because of their religious and ethnic identity."

He continued by urging Muslim leaders to denounce IS and all acts of terrorism.

"As religious leaders, we are obliged to denounce all violations against human dignity and human rights," he said.