ISLAM QALA, Afghanistan (AFP) —Tens of thousands of Afghans streamed over the border from Iran in the days before a return deadline set for Sunday, the United Nations (UN) said, sparking an “emergency” situation at border points.

In late May, Iran said undocumented Afghans must leave the country by 6 July, potentially impacting four million people, out of the six million Afghans Tehran says live in the country.

Numbers of people crossing the border have surged since mid-June, with a peak of more than 43,000 people crossing at Islam Qala in western Herat province on 1 July, the UN refugee agency UNHCR said on Friday.

The UN migration agency IOM said more than 250,000 Afghans returned from Iran in June.

UNICEF country representative Tajudeen Oyewale said this was an “emergency” situation in a country already facing a “chronic returnee crisis,” with 1.4 million Afghans returning from traditional hosts Iran and Pakistan this year.

“What is concerning is that 25 percent of all these returnees are children... because the demographics have shifted” from individual men to whole families, crossing the border with scant belongings and money, he told Agence France-Presse on Thursday.

He noted Islam Qala could accommodate the vast numbers but was inadequately equipped in terms of services, saying, “When you start hitting more than 20,000 people (a day) that is completely beyond the planning scenario that we have.”

The agency has engaged emergency processes to ramp up water and sanitation systems built for 7-10,000 people a day, along with vaccinations, nutrition and child-friendly spaces.

Many people crossing reported pressure from authorities or even arrest and deportation.

“Some people are so afraid that they don’t leave the house themselves... They send their young children out just for a piece of bread."