Thousands of Iraqi Christians are on the run after militants belonging to the Islamic State in Iraq and Syria (ISIS) advanced into and overran the country's largest Christian city, Qaraqosh, in northern Iraq.

A French government spokesman confirmed the fall of Qaraqosh, a city of 50,000 inhabitants, about 20 miles to the southeast of Mosul, Iraq's second-largerst city, which had earlier fallen into ISIS hands.

Like Us on Facebook

When Mosul was overrun, thousands of its Christian residents had fled to Qaraqosh after the ISIS gave them an ultimatum to convert to Islam, or "face death by the sword."

Now, the Christians of Qaraqosh are fleeing north toward Kurdistan.

Statements from Chaldean Christian leaders in the U.S. said the ISIS have resorted to "beheading children and raping women" and hanging fathers in the areas they have overran in the north, to terrorize Christians and convince them to convert.

Interviewed by CNN, Chaldean-American businessman Mark Arabo in San Diego said they are receiving reports from their members in Iraq about the persecution of Christians by ISIS militants, saying the "world hasn't seen an evil like this for generations." 

After Mosul was overrun, the ISIS "actually beheaded children and put their heads on a stick and have them in the park," Arabo explained. 

"More children are getting beheaded, mothers are getting raped and killed, and fathers are being hung," he said.

France has called for an emergency meeting of the United Nations Security Council to discuss the situation in northern Iraq.

"France is highly concerned about the latest progress of ISIS in the North of Iraq and by the taking of Qaraqosh, the largest Christian city of Iraq, and the horrible acts of violence that are committed," French Foreign Minister Laurent Fabius said in a statement.

Meanwhile, the United States is considering emergency air drops of food and water for thousands of stranded Christians and Yazidis in northern Iraq.

About 40,000 Yazidis, a religious sect located in northern Iraq, Syria and the Caucasus, were said to have fled from the city of Sinjar not far from Mosul and are stranded, along with thousands of Christians from Qaraqosh, in the mountains trying to get to Kurdistan.