Once a week, the children trail in slowly from the rain forest on stick-like legs. Their rib cages protrude through skin pitted with sores and swellings, their faces have prematurely aged. One boy, barely six years of age, carries his younger brother, grey-haired from malnutrition, on his back for the entire 20-mile journey.
Patiently, listlessly, they wait in line for a ration of maize and soya provided by a British charity, Children's Aid Direct. Then they disappear again into the forest, the combat zone of Burundi's civil war, where there is no food, no medicine and, probably, very little future for these children.
Aid workers who are veterans of Zaire and Somalia say the levels of hunger in the war-ravaged provinces of north-western Burundi are among the worst they have seen. Thousands of children may be starving to death in a hidden famine caused by the civil war and the catastrophic failure of the last harvest.
But no one can really tell the death toll in this most underreported of African tragedies. The dense forests where Hutu rebels have operated since 1993 are out of bounds to western aid agencies because of heavy fighting and the danger of landmines.
Mr Dominic MacSorley, country director of Concern, says the crisis is as bad as anything he witnessed among the fleeing refugees in eastern Zaire last year.
"The main problem is access, which is beginning to improve. We're only now seeing what's coming out of the mountainous areas, and the picture is much more serious than anyone thought."
The UN High Commissioner for Refugees, Ms Sadako Ogata, was due to arrive in Burundi yesterday and is scheduled to travel to some of the worst-affected areas in Cibitoke province.
In the absence of hard information, the best guide is the evidence of one's own eyes. The children arriving at the feeding station in Bubanza town yesterday, all of them dressed in the filthiest of rags, have the classic symptoms of malnutrition.
The irritable ones with wizened faces, white hair and flaking skin are marasmic, a condition which results from a chronic lack of calories. Others have kwashiorkor, a protein deficiency which leads to skin oedemas and loss of pigmentation, as well as listlessness. More than 3,500 children a week stream into the feeding station in such condition.
What these children need is hospital care and a special therapeutic feeding programme. Yet, for months the Burundian government, controlled by Tutsi bureaucrats in the capital, Bujumbura, has been dragging its heels on proposals by a number of bodies, including Concern, to establish therapeutic care programmes in the affected areas.
As a result, there is no medical care for the worst-affected children although they appear to be dying on their feet.
"It's terrible, these are some of the most severe cases of malnutrition I have come across," says Mr Patrick Lavand'Homme, head of Children's Aid Direct.
In Cibitoke province the picture is the same. There, Concern is to take over the running of two therapeutic feeding centres. Yesterday, the centres were filled with hundreds of sick and malnourished children and adults. At Gasenyi, these included a number of six-month old babies weighing less than 2.5 kilograms.
The UN estimates that about 600,000 people in Burundi are in danger of starvation because they are unable to reach their farms. In Bubanza province alone, almost half of the 180,000 population is thought to be severely malnourished. Bubanza town itself largely consists of tarpaulin shelters hastily erected by refugees fleeing from the fighting.
For security reasons, the World Food Programme, which normally distributes food in such emergencies, has been unable to assess malnutrition levels in the war-affected regions. And because no assessments have been carried out, the WFP is prevented by UN rules from distributing food to the very areas which need it most.
Last December's harvest yielded only 30 per cent of its normal capacity, due to heavy rainfall and the effects of the civil war.
Meanwhile, emergency food supplies for Burundi have run out. Trucks carrying food from ports in Tanzania have been trapped by heavy rainfall, blamed on the El Nino phenomenon, which has caused fallen bridges and blocked roads. The WFP is considering airlifts of food to the country.
In recent months, the army has begun to gain the upper hand in its five-year conflict with Hutu rebels. Its size has been boosted from 15,000 to 60,000 troops. Many southern provinces are quieter than they have been for years. Areas in Bubanza and Cibitoke provinces which were previously no-go areas are now opening up to some extent. However, minor roads are still heavily patrolled by soldiers.
Nonetheless, the rebels still managed to carry out a spectacular attack on the airport at Bujumbura at the New Year. Over 200 civilians died in crossfire between government troops and a force of 1,000 Hutu rebels. Fighting continued around the capital throughout January.
Bujumbura is now a Tutsi bastion, underpinned by a form of black apartheid. Each morning, thousands of Hutu employees who have been evicted from the capital can be seen walking in from their "townships". Every evening, they walk home again and the city is effectively closed by armed guard at 5 p.m.
Up to one million Burundians out of a population of six million have been displaced from their normal homes because of the fighting. Many have been forced by the army into temporary camps without access to clean water or land on which to grow crops.
According to Mr Mark Mullen, the representative of the European Community Humanitarian Office (ECHO), the problem of malnutrition in Burundi is "one of the most alarming in Africa". Mr Mullen, who comes from Dublin, says Burundi is "not quite a forgotten conflict, but it isn't exactly on everyone's map".
UN human rights monitors are confined to Bujumbura. Even the International Committee of the Red Cross - regarded as the diehards of international crises - withdrew from the country in 1996 after three of its workers were murdered.
"Burundi is a country in crisis, yet it is always regarded as a sideshow to Rwanda. The genocide and the subsequent international guilt ensure that Rwanda remains on the public stage," says Mr MacSorley.
Concern returned to Burundi last August to carry out nutrition surveys in a number of areas. For a number of months, it has been ready to provide feeding programmes in the war-affected regions, but is still waiting on the authorities to give authorisation.
Aid agencies say sanctions which were imposed on Burundi following a military coup in 1996 have failed. Food prices have doubled, severely affecting the poor, yet the sanctions have been a boon to smugglers and Bujumbura's shops are full of luxuries.
Should anyone in Ireland care about Burundi's problems? Mr MacSorley thinks so: "Because nobody else does. Because the needs of the people are so great. And because areas which were cut off by fighting are now opening up, we have the chance to make a real impact."