But Afghans affected by the campaign claim that even legally registered refugees are being forced to leave. They say those who remain in Iran face pressure that makes it difficult for them to survive.
Afghan Foreign Minister Rangin Dadfar Spanta says Iran should immediately stop repatriating large numbers of Afghan refugees because Afghanistan does not have sufficient resources to help them resettle.
Spanta told RFE/RL's Radio Free Afghanistan that the reported expulsion of 50,000 Afghan refugees from Iran during the past two weeks is contributing to instability in Afghanistan.
"The massive expulsion of Afghan refugees [from Iran] is against the friendly and neighborly principles between our two countries," Spanta said. "It's very unfortunate that, on one hand, Iran is helping Afghanistan with reconstruction in order to build stability but, on the other hand, is expelling the Afghans en mass. This causes instability for Afghanistan. We are not able to provide the thousands of returning refugees with a place inside Afghanistan."
Authorities in Tehran say they are only expelling those Afghans who are living illegally in Iran and have failed to register their presence.
A statement issued by Iran's Interior Ministry stresses that only refugees with valid documents may stay in Iran. The statement also argues that every country has sensitivities about "illegal citizens" on its territory. It says the presence of so many Afghan refugees has created "political, social, economic, and security consequences" for Iran.
Millions of Afghans fled to Pakistan, Iran, and Central Asia to escape the wars that have devastated Afghanistan since the Soviet invasion of 1979.
Iran accepted several million Afghans -- mostly Shi'ite Hazara or Sunni Persian-speaking Tajiks.
Since the collapse of the Taliban regime in late 2001, Iran has been working with authorities in Kabul and the United Nations High Commissioner for Refugees (UNHCR) on a voluntary repatriation program.
Illegals 'Not Of Concern' To UN
Vivian Tan is a spokeswoman for the UNHCR's Southwest Asia office in Islamabad -- the office responsible for UNHCR activities in Iran, Afghanistan, and Pakistan.
Tan told RFE/RL that the UNHCR's mandate is to help those individuals who have the legal status of refugees. Afghan refugees in both Pakistan and Iran must therefore be legally registered in their host country to qualify for UNHCR aid.
"Anyone outside of this group who was not around to register is not of concern to UNHCR. They are not refugees," Tan said. "They are not of concern. Everybody who is not registered is considered an illegal migrant. In Iran, from what we know, the recent deportations are of unregistered Afghans. So these are people who did not take part in the registration and did not get the [reintegration] cards that were issued by the Iranian government."
But some Afghan refugees tell a different story.
Several Afghans tell RFE/RL that Iranian authorities in the past two weeks confiscated and destroyed their registration cards before expelling them from the country.
Others say their money and personal property -- even extra clothing -- was confiscated by Iranian authorities before they were forced across the border back into Afghanistan.
...But Legality Is Not Everything
Haqdad, an Afghan refugee originally from Ghazni Province, is still living in Iran. But he says Tehran's repatriation campaign makes life difficult even for those who are legally registered.
"We live in a very difficult situation here because the [Iranian authorities] detain us and send us to the other side of the border," Haqdad said. "There are even some families whose wives remain here but their husbands have been sent to the other side of the border. The Iranian officials who detain us take all the money we have in our pockets."
Agha Mussa, an Afghan refugee from Herat, in western Afghanistan, who also is struggling to survive in Iran, says many Afghans he knows have been beaten by Iranian police -- alleging there is a campaign of intimidation aimed at driving out all Afghans refugees, regardless of whether they are registered or not.
Afgha Mussa told RFE/RL that many Iranian employers are taking advantage of the vulnerability of Afghan refugee laborers by refusing to pay them wages that they are owed.
"We -- refugees living in Iran -- are under a lot pressure," Afgha Mussa said. "Our jobs are left here. The employers don’t pay our money. We are being detained and sent out of the border. They harass us and they beat us."
Tan said UNHCR officials have not heard such complaints. But she said any legitimate refugee who is being intimidated in Iran or Pakistan can get help from her organization.
"Even if you are an unregistered Afghan in Pakistan or Iran, UNHCR's doors are always open," Tan said. "So if you wish to claim asylum, you are free to come in and protest. If you have the proper grounds and you are recognized as a refugee, then we will offer you the protection that you need in the host country -- in Iran or in Pakistan."
Afghan Interior Ministry spokesman Zemeri Bashary confirmed that Afghan refugee families are being separated by Iran's expulsion campaign.
Beshary said those being repatriated also face other serious problems when they arrive back in Afghanistan -- including a lack of food, employment, and shelter.
"These problems are a result of a lack of a system and also haste in this work," Beshary said. "I say, once more, that we are willing to have more cooperation with our friendly [neighbor], and we hope that they will provide us assistance regarding this issue."
The UNHCR has helped provide resettlement aid to millions of repatriated Afghan refugees since the start of 2002.
That includes a six-week campaign earlier this year in which Pakistan repatriated 200,000 unregistered Afghans who had been living in Pakistan.
(RFE/RL's Radio Free Afghanistan contributed to this report)