New Delhi, July 29 -- a customer service role in Southeast Asia, competitive salary, English fluency required. Some found it on LinkedIn. Others received it through Facebook groups for university-educated professionals in their 20s and 30s. When they arrived, their passports were taken.

That is how 300,000 people ended up inside scam call center compounds in Myanmar, Cambodia, and Laos, the International Organization for Migration said Monday, describing what it called the fastest-growing form of human trafficking in the world. Speaking at a briefing in Geneva, IOM Director General Amy Pope said victims are held against their will, forced to conduct romance scams, investment fraud, and cryptocurrency schemes online, while living under th...