Editor's note: Joe Stork is the deputy director of the Middle East and North Africa division at Human Rights Watch. The opinions expressed in this commentary are solely those of the author.
Irbil, Iraq (CNN) -- The offensive by ISIS militants against civilians and religious minorities in the northern Iraqi governorate of Nineveh has created a catastrophe.
At least 300,000 Yazidis and 100,000 Christians were displaced literally overnight, according to figures provided by the Kurdistan regional government. Many of the Yazidis fled to the mountains on August 3 after Kurdish fighting forces known as Peshmerga, who were protecting them, precipitously withdrew. For the Christians in villages north of Irbil, the moment came in the wee hours of August 7, when the Peshmerga silently pulled out.
The thousands of Yazidis who had remained stranded on a mountain seem to be getting out for now after U.S. airstrikes helped clear a safe path for escape. But even if they reach a safer place in Iraqi Kurdistan, their longer-term prospects are grim as long as forces of ISIS, which refers to itself as the Islamic State, control the area where they lived.
On August 6, I visited a Yazidi village south of Duhuk -- a magnet for 60,000 to 70,000 of the fleeing Yazidis. They had bread and water but not much else.
Many more -- upward of 150,000 -- were on the rugged mountains a dozen or so kilometers north of Sinjar. They found little sustenance or shelter amid the mountains' sparse vegetation and summer temperatures of up to 120 degrees Fahrenheit. Perhaps 40,000 managed to escape on the northern side that day before ISIS surrounded the mountains.
Over the following days, a few thousand more trickled out in small groups, braving ISIS snipers as they made their way north.
The latest U.N. field reports say an average of more than 10,000 people a day have been crossing from Syria into the Kurdish region of Iraq by a small bridge at Peshkhabour. Most are Yazidis, who had managed to make it down from the mountains and into Syria, about 20 kilometers (about 12 miles) away.
The Yazidis are ethnically related to Kurds but practice a 4,000-year-old religion. ISIS -- indeed many Muslims -- consider them to be "devil worshippers," and the militants seem intent on eliminating them as a religious community and culture.
Indeed, Yazidis were the target of what was probably the worst attack against civilians in Iraq since the U.S.-led invasion in 2003. On August 14, 2007, four simultaneous bombings involving a fuel tanker and three cars killed upward of 500 Yazidis, wounded more than 1,500 and destroyed nearly 400 homes. The explosions were so huge that no trace could be found of dozens of people closest to the explosions.
There was no Iraqi government investigation. No group claimed responsibility, but it was typical of bombings by the Islamic State of Iraq, predecessor to ISIS, which had reportedly distributed leaflets in the area shortly beforehand denouncing Yazidis as "infidels."
The ISIS strategy since capturing Iraq's second-largest city, Mosul, a month ago is apparently to clear Nineveh -- home to many of Iraq's religious minorities -- of civilians and anyone who isn't a Sunni Muslim. An ISIS photo spread distributed shortly after the capture of the Yazidi village of Sinjar showed the militants executing people who were clearly civilians.
At least a dozen Yazidi men told me in the past week that ISIS had abducted scores of women and girls, detaining large numbers in a school in Tal Afar, a town northwest of Mosul. Others were trucked across the Syrian border to a detention center.
Asad, a young Yazidi man working in Irbil at the time of the attack, said ISIS abducted 50 members of his extended family as they tried to escape and forced them to drive across the Syrian border. His brother Raad drove one of the cars, his cell phone open on his lap, on speaker, while Asad in Irbil kept adding funds from scratch cards to keep the line open. Raad described over four hours the route that ISIS forced the captured family to drive into Syria.
"I lost contact then," Asad said. The next day he tried the numbers of another brother. Someone else answered. "Do not call," that person said. "We have all their mobiles, we don't know where they are," and hung up.