SAN DIEGO - The radical Islamic group ISIS is making good on its threats to kill Iraqi Christians who refuse to convert.
The crisis is closely being followed by San Diego's Chaldean community, which is the second largest population of Iraqi Christians in the United States.
Local Chaldean leader Mark Arabo says what is happening in Iraq right now is truly a living nightmare.
"It's literally the worst it's ever been, not just for Chaldeans but for Christianity for the entire region," said Arabo, who is president of the Neighborhood Market Association.
The violence in Iraq has already displaced more than a million Iraqis of many faiths. Arabo explains that families' homes are being marked.
"This is their red stamp right here, that they are marking Christian homes," he said as he pointed to a photo from Iraq. "They are basically saying, 'We know who you are and when the holy month of Ramadan is over, your lives are in our hands.'"
Arabo says it is an all-too familiar reminder of what was done during the Holocaust, when Star of David symbols were painted on homes and businesses of Jewish people during the Nazi regime in Germany.
"This is a global humanitarian crisis and a Christian Holocaust is in our midst," Arabo added.
Fighters of the Islamic state of Iraq and Syria – or ISIS – have swept across Northern Iraq from Syria, leaving the red stamps and notes on doorsteps in their quest to take over Iraq.
"They are saying you need to convert to Islam, pay a fee or leave," said Arabo.
Or else many are facing mutilation, rape or beheading.
"We have to make sure we don't turn a blind eye to another Holocaust," said Arabo.