Christians living in the Middle East are facing a dire situation in which comparable circumstances have not been observed for over a millennia, a recent study by the Pew Research Center has found, Christianity Today reports. The outlet notes that Christian populations in the Middle East have dwindled from 14 percent to four percent.

Much of the blame for the endangered situation concerning Christian communities of the Middle East is due to the rise of the Islamic State (ISIS) terror group, which views Christians as a mortal enemy. ISIS propaganda pamphlets often refer to Christian-majority countries as “crusader” armies.

Last week, the New York Times released a major report of its own highlighting the persecution of Middle Eastern Christians. The Times reported that only one-third of what was a 1.5-million strong Iraqi Christian population in 2003 has remained in the country, and some 200,000 Syrian Christians have fled their homes.

Rep. Anna Eshoo (D-CA) told the Times, “Christianity [in the Middle East] is under an existential threat.”

The Guardian also published a story on the same topic Monday, focusing on the plight of Christians worldwide. The UK paper highlighted a Pew study that showed Christians face persecution in 102 countries. To make matters worse, a 2014 report showed that conditions for Christians have “deteriorated” in at least 55 countries

Additionally, the Commission on International Religious Freedom (USCIRF), a U.S. government advising body, charted eight countries—seven of which maintain a large Islamic population—to add to a growing list of “countries of particular concern.”

The USCIRF advised the U.S. government that in order to combat religious persecution, more effort must be put into defeating jihadist groups like ISIS and al-Qaeda.

“One of the 21st century’s major challenges to freedom of religion or belief [is] the actions of non-state actors in failing or failed states,” said an excerpt from the USCIRF 2015 report.