The number of Afghans coming home from Iran has doubled in the past month, a top border official said Wednesday, with returnees reporting growing pressure to leave.

At least 14,480 Afghans have crossed at Islam Qala in four days since the weekend, said Abdullah Qayomi, head of refugee affairs at the busy crossing near the western Afghan city of Herat.

Afghans deported from Iran carry their belongings to a registration centre near the Islam Qala border crossing in Herat province.

The rise comes as Afghanistan's eastern border points with Pakistan have been inundated with returnees after Islamabad ordered 1.7 million Afghans it said were living illegally in the country to leave or face deportation.

"When Pakistan made the decision to deport our countrymen from their own land, the figures started to rise here," Qayomi said.

"The figures have doubled now as compared to one month ago," he told AFP this week, saying numbers leapt from 1,500-2,000 per day to 3,000-4,500.

"Iran has not announced it (that they are deporting Afghans) but continuously there is no decline in our figures, they are only increasing day by day," Qayomi said.

Afghans arriving at Islam Qala report being detained and deported, even if some of them had documents allowing them to be in Iran.

Abdul Rahim Ahmadi said he had been living in Iran for 11 years with proper documents but was arrested with his nephew and taken to a military base before being deported through Islam Qala on Monday.

"No questioning happened, they just brought us to the military base... and just like that I was deported," the 47-year-old told AFP.

"My wife and son are there in Iran, I have rented a house there. I don't know what to do."

Iran, which shares a 900-kilometre (560-mile) border with Afghanistan, hosts one of the largest refugee populations in the world, made up mostly of well-integrated Afghans who arrived over the past 40 years after fleeing conflict.

An estimated 4.5 million Afghans currently live in Iran, according to the International Organization for Migration, though Tehran estimates there are more than five million.

The agency said in a 2023 report the number of Afghans leaving Iran outstrips those entering, "mainly due to the systematic pushbacks" by the Iranian government.

Iranian officials did not respond immediately to requests for comment on the uptick in Afghan returnees in recent weeks.

But Iran's official IRNA news agency quoted a police official this month as saying more than 15,000 "illegal" Afghan citizens had returned over just four days, and some 328,000 were deported this year.

An Afghan delegation led by Deputy Prime Minister for Economic Affairs Mullah Abdul Ghani Baradar Akhund visited Tehran last week.

A statement from Afghan authorities said Iranian Foreign Minister Hossein Amir-Abdollahian pledged to resolve "refugee-related issues" during discussions on boosting trade ties.