The Geneva-based International Organization for Migration reports time is running out for a group of 5,000 displaced people who have been on a 435-mile trek back to their homes in southern Sudan.

Since they began their trek nearly three-months ago, the 5,000  Sudanese have crossed parched riverbeds, cut their way through thick forest brush and swamplands. The International Organization for Migration says the group decided not to take a more direct route that is heavily mined.

The displaced Sudanese began their journey from a camp in Western Equatoria province. They fled there in October 2001 from Western Bahr-El-Gazal province to escape civil strife.

An IOM spokeswoman, Jemini Pandya, says the Sudanese were supposed to have left a makeshift camp in Fala Walla, on the border with the Central African Republic, last week. But she says that part of the journey was slowed by, what she called, very, very difficult conditions.

"The operation has fallen back by a week," she said. "There has been lots of marshes to cross, and the new fuel supplies, which were supposed to be taking IDPs (internally displaced persons) from where they were last week to Deim Zubeir, were very late getting to a camp in Fala Walla last week, because of the fuel trucks being stuck in the marsh."

Ms. Pandya says the group has finally left Fala Walla on the next leg of the journey. But the going is painfully slow. She says most of the people are on foot. But she says, until this latest delay, IOM had been transporting 1,600 elderly or sick people, children and pregnant women.

"The trucks are suffering very badly because of the conditions, obviously, that they are having to operate in. So, we are not able to transport as many people as we had been beforehand," she said. "Now, it is more a question of transporting between 700-and-800 of the really, really vulnerable IDPs; whereas, before, we were transporting 1,600, and more people are having to walk. It is probable that another food drop will be needed by the end of next week."

Aid agencies have been helping the Sudanese, largely from a distance. The International Organization for Migration, World Food Program, UNICEF and Doctors Without Borders have been supplying them with food and medicine through occasional air-drops.

Ms. Pandya says the journey is taking a heavy toll. She says there have been a few deaths in the past two weeks, including a few elderly people and a baby. She says it is difficult to know whether the displaced Sudanese will reach their homes in Raga in Bahr-el-Ghazal province before heavy rains arrive.

She says the group decided to go home on its own after a peace deal was signed in January between the mainly Muslim north and the animist and Christian south. That agreement ended 21 years of civil war.