More than half a million Afghans have been expelled from Iran in the 16 days since the conflict with Israel ended, according to the United Nations, in what may be one of the largest forced movements of population this decade.

For months, Tehran has declared its intention to remove the millions of undocumented Afghans who carry out lower-paid labor across Iran, often in tough conditions.

The International Organisation for Migration (IOM) has said 508,426 Afghans have left Iran via the Iranian-Afghanistan border between June 24 and July 9.

A startling 33,956 crossed Wednesday and 30,635 on Tuesday, after a peak of 51,000 on Friday, ahead of a Sunday deadline from Iran for undocumented Afghans to leave.

The deportations – part of a program Iran announced in March – have radically increased in pace since the 12-day conflict with Israel, fueled by unsubstantiated claims that Afghans had spied for Israel prior to and during the attacks. Scant evidence has emerged to support claims of Afghan migrants assisting Israel has emerged, leading critics to suggest Iran is simply fulfilling a long-held ambition to reduce its illegal Afghan population and focusing internal dissent on a vulnerable minority.