Khan's children were killed when unexploded ordnance (UXO) went off near their home in Itehad Returnees' Township, about 20km from Pol-e-Khomri, the provincial capital of Baghlan Province in northern Afghanistan.
"We thought it would be safe here," the bereaved father told IRIN.
UXOs and explosive remnants of war have also been reported in other returnees' settlements in the eastern provinces of Nangarhar and Kunar. Hundreds of thousands have returned there in the past few years.
"About 200 metres from our settlement the area is full of landmines and explosive devices which often kill animals," said Mohammad Afzal, a resident of a settlement in Nangahar Province.
Provincial officials said mine-clearing agencies had been asked to re-examine areas in Baghlan and Nangarhar provinces for any hazardous explosives.
The Refugees and Returnees' Ministry, however, said it allocated settlement sites for landless returnees after mine-clearing agencies declared those areas risk-free.
Returnees strain resources
According to the UN Refugee Agency (UNHCR), more than five million Afghan refugees have returned to their home country since 2002, primarily from neighbouring Pakistan and Iran, and 4.3 million of them had been assisted by the organisation.
Over 276,000 refugees returned to the country between January and the end of October 2008, official figures show.
"For the sixth consecutive year, this is the largest voluntary repatriation programme worldwide," said Ewen MacLeod, UNHCR's acting representative in Afghanistan. "We are certainly not aware, in recent history, of any country that has absorbed so many people in such a short time."
The UNHCR said all refugees had returned voluntarily.
The influx of returnees since 2002 has swelled the Afghan population by 20 percent, according to the UNHCR, and has put increasing strain on already limited resources and services in the war-ravaged country, ranked the fifth least developed in the world by the UN Development Programme.
The return to Afghanistan has been described as impressive and unprecedented, but the overall repatriation trend has declined since 2006.
Between 2002-2005 most returnees (more than three million) were those who had left the country for a relatively short period and were quickly re-absorbed.
"Since 2006 the return, and particularly the re-integration, challenges have become more difficult, mainly because the majority of those involved have now been absent from the country for more than 20 years. And indeed, half of them have been born outside Afghanistan," MacLeod said.
The worsening security situation, lack of socio-economic opportunities, lack of access to basic services such as health and education, food insecurity, and natural disasters have been other major factors impeding return, according to aid agencies.
About 2.78 million Afghans are still registered as refugees in Pakistan and Iran, the UNHCR says.
The UNHCR and the government are due to host an international conference in Kabul sometime in November (exact dates to be announced later) to assess various aspects of future returns to Afghanistan.
"The conference is an opportunity for the government, countries of the region and donor countries, to come together and see how best repatriation and reintegration can be supported in the future - at what level, and just as importantly, how it can be made sustainable," MacLeod said.