August 21, 2014 9:10 PM
The United Nations has launched what it describes as one of the biggest aid operations in 30 years in northern Iraq, as hundreds of thousands of refugees flee the extremist Sunni militant group calling itself the Islamic State. As Kurdish and Iraqi forces battle the Sunni insurgents, the fighting has forced more people to flee their homes. Kurdish authorities say the international community must act now to avert a humanitarian catastrophe. Henry Ridgwell reports for VOA from London.