Pakistan, July 7 -- Nearly 450,000 Afghans have returned from Iran since June 1, the United Nations' migration reported on Monday. This surge follows Iran's order for undocumented Afghans to leave the country by July 6.

From June 1 to July 5, a total of 449,218 Afghans crossed back into Afghanistan, raising the yearly return count to over 900,000. Tens of thousands hurried to cross the border before the deadline, creating an emergency situation at key border points.

Iran's return deadline affects nearly four million undocumented Afghans living in the country, out of the six million Afghans Tehran says reside there. The border crossing at Islam Qala saw a peak of over 43,000 people in one day, according to the UN refugee .

UNICEF expres...