Sister Diana Momeka had been invited before the foreign affairs committee of the US House of Representatives to testify about ancient communities that were being destroyed, and Islamic State's (IS) gains in the region.
According to Christian News Wire, Sister Momeka, a Dominican sister, was forced to flee from Mosul in Iraq when her convent was bombed.
She said IS persecution of Christians is the worst believers in the region have experienced for more than 1000 years.
Speaking to the house, she said: "Nineveh was emptied of Christians, and sadly, for the first time since the 7th century AD, no church bells rang for Mass in the Plain of Nineveh."
"The loss of the Christian Community from the Plain of Nineveh has placed the whole region on the edge of a terrible catastrophe.
"This uprooting, this theft of everything that the Christians owned, displaced them body and soul, stripping away their humanity and dignity."
"I call on all Americans to raise your voices on our behalf so that diplomacy and not genocide, social well-being and not weapons, and the desire for justice, not selfish interests determine the future for Iraq and all of her children."
The House heard that people had fled the area with little more than the clothes they were wearing, when the church came forward to help.
She said: "Thankfully, the Church in the Kurdistan region stepped forward and cared for the displaced Christians, doing her very best to handle the disaster.
"Church buildings were opened to accommodate the people; food and non-food items were provided to meet the immediate needs of the people; and medical health services were also provided.
"Moreover, the Church put out a call and many humanitarian organizations answered with aid for the thousands of people in need.
"There are many who say "Why don't the Christians just leave Iraq and move to another country and be done with it?" To this question we would respond, "Why should we leave our country - what have we done?"
