Nearly 450,000 Afghans have returned from Iran since 1 June after Tehran ordered undocumented migrants to leave by 6 July or face detention, the UN’s International Organization for Migration said on 7 July. The figure represents one of the fastest population movements in the region in recent decades. The outflow accelerated sharply ahead of the deadline, with crossings at the Islam Qala border post in western Herat province topping 40,000 a day. IOM data show more than 230,000 people—about half of them forcibly deported—left Iran in June alone, underscoring the scale of the crackdown. Iranian authorities say the expulsions are driven by security concerns following last month’s 12-day conflict with Israel and warn that as many as four million undocumented Afghans may have to depart. Aid organisations dispute the security rationale and report daily returns now approaching 50,000, raising fears of a wider humanitarian crisis in Afghanistan. UNICEF and the Red Cross describe an “emergency” at the border as exhausted families arrive with scant belongings. Funding shortfalls mean the IOM can assist only about 10 % of those in need, while the Red Cross projects up to one million additional returns by the end of the year. UN agencies have appealed for more international support, warning that the sudden influx could overwhelm Afghanistan’s fragile economy and deepen regional instability.