KABUL -- The United Nations High Commissioner for Refugees (UNHCR) said the situation is not favorable for the four million Afghan refugees who have returned to the war-torn country after more than two decades of civil unrests.

In a communique issued Saturday in Kabul, the UNHCR said the security and dearth of food are among the main concerns of the Afghan and UN officials in Afghanistan.

It said the donors have to provide assistance for the UNHCR to provide food and shelter for the Afghan returnees, IRNA reported.

It said since March some 1.8 million Afghan refugees have come back to Afghanistan.

The officials are after setting the food problem during the cold season to prevent happening of a human catastrophe, the same source said.

It said plans need to be drawn up to provide shelter for the homeless within a short period of time.

The massive refugee camp of Maslakh in Afghanistan's historic western city of Herat, stands as a sharp reminder of the challenges destitute Afghans face, even after the collapse of the Taleban last year.

Reportedly, more than 100,000 men, women and children struggle to survive in the squalid camp -- almost half have been there for almost a year. Many face a harsh winter under makeshift shelters with just basic food and medicine, UNHCR said earlier.

Their plight is common to hundreds of thousands of Afghan IDPs (Internally Displaced Persons) who have been made homeless by decades of conflict and an ongoing drought.

According to an assessment by UNHCR and its partners, roughly over half a million IDPS and former refugees throughout Afghanistan will be in need of assistance during the winter, particularly for shelter, food, water, health care, and non-food related assistance.

Refugees' ordeal portrays the tragedy of hundreds of thousands of Afghan nomads, whose animals were killed by drought or lost while fleeing ethnic persecution in northern Afghanistan.

Most of the nomads have ended up in displacement camps around the country, but some live in scattered villages, receiving little assistance.

The post-11 September U.S.-led military campaign in Afghanistan and the anarchy after the fall of the Taleban displaced yet more people.

Some of the ethnic Pashtuns -- constituting the majority of IDPs in the western region -- were forced to abandon their villages or give up their animals when ethnic militias loyal to local warlords started settling scores after the demise of the Pashtun-dominated Taleban.

Although the total number of IDPs in western Afghanistan is hard to determine, some estimate that more than 100,000 might be staying in the five camps in and around Herat.

More than 80,000 of them returned to their villages -- mostly in the three provinces of Herat, Badghis and Ghowr -- under a program supervised by the International Organization of Migration (IOM).

Diarrhea and respiratory diseases are common in the crowded environment. But Maslakh, named after the once-functional slaughterhouse near the camp, has always been a symbol of Afghan suffering long before 11 September 2001.