Pope Francis
Pope FrancisUri Lenz/POOL/Flash 90

Pope Francis strongly condemned genocide against Christians in the Middle East on Thursday, stating during a Papal visit to Bolivia that the phenomenon is a "third world war." 

"Today we are dismayed to see how in the Middle East and elsewhere in the world many of our brothers and sisters are persecuted, tortured and killed for their faith in Jesus," he said.

"In this third world war, waged piecemeal, which we are now experiencing, a form of genocide is taking place, and it must end."

Over the past 100 years, Islamic fundamentalism in the Middle East has reduced the total representation of Christians in the region from 20% in 1900 to around 5% as of March 2015, according to Newsweek - or less than 1% of the world's estimated 2 billion Christians.

While exact numbers are hard to define, given the chaos in several Middle Eastern countries, one European Parliament report in March suggests that some 700,000 Christians have fled Syria, for example - of a total of some 1.1 million estimated to have been living there before 2011. And in Iraq, the Christian population has shrunk from 1.4 million in 2003 to barely 250,000 today.

Terror group Islamic state (ISIS) is estimated to have accelerated the mass exodus of the Middle East's Christians, and has made clear that it is waging a war on Christianity, noting that Rome is a key target for conquest as the home of the Vatican and a core symbol of the religion.

Francis has been particularly vocal about the future of the Middle East in a series of comments in December 2014, condemning ISIS and calling for interfaith cooperation in order to combat it.

"It is essential that all citizens - Muslim, Jewish and Christian - both in the provision and practice of the law, enjoy the same rights and respect the same duties," the pope said at the time.

He later called for “dialogue” with ISIS, but later conceded that such dialogue is "almost impossible."

The pope's Vatican late last month signed its historic first accord with "Palestine," even though it has yet to sign such an accord with Israel. 

The accord comes despite the fact that Christians have been systematically persecuted under the Palestinian Authority (PA), which has caused the Christian population in Bethlehem to nearly disappear from 60% in 1990 to 15% last year.