United Nations aid agencies are mobilizing a huge relief operation for the hundreds of thousands of people affected by the devastating earthquake that struck the Indonesian island of Java Saturday. The quake killed more than 5,000 people and left an estimated 200,000 homeless. 

The United Nations office that is coordinating the relief effort says the situation is under control despite the complexity of the operation. Spokeswoman Elizabeth Byrs says coordination centers have been set up in the city of Yogyakarta, the epicenter of the quake, in the nearby town of Bantul and at the airport.

She says the response to the disaster was efficient and rapid. U.N. staff members working on tsunami relief in Indonesia and soldiers from the Indonesian army were immediately dispatched to Java. But Ms. Byrs says many problems lie ahead.

"It is the logistic problem, the rains, the communications, the storage, the congestion of the airport and the airstrip and all these usual problems that we meet when there is a disaster," she said.  

Damaged roads, heavy storms and rain are complicating the relief effort. Telecommunications are down. Supplies of water and electricity have been affected. Nevertheless, aid is pouring into the area.

Some 400 volunteers and staff from the Indonesian Red Cross who were stationed at Mt. Merapi, a volcano located near Yogyakarta, quickly went to the earthquake zone. A spokeswoman for the International Red Cross Federation, Anna Nelson, says the volunteers have treated at least 4,000 injured people. She says various Red Cross societies have rushed tons of food and non-food supplies to the region.

"We have a water and sanitation unit on the way which should arrive within the next two days and can produce 600,000 liters of drinking water per day," she said. Two-thousand tents have arrived in the earthquake zone and another 10,000 are on their way. In addition the International Federation has deployed three, what we call, emergency response units to provide assistance in the areas of logistics relief and information and telecommunications."

The World Food Program already has dispatched 70 tons of high-energy biscuits and packets of noodles to the victims. Spokesman, Simon Pluess says a big chartered plane arrived in Java Tuesday carrying more food and tons of non-food items such as blankets, tents, generators and water pumps.

"Our assessment teams on the ground have indicated that around 100,000 people were directly affected by the earthquake and may require food aid for about two to three months," he said. "The markets in Bantul and Klaten are still closed. That means that all these people who have lost their own food stocks in the earthquake will rely on the emergency food rations."

The U.N. children's fund says about 40 percent of the victims are under 18 years of age. The agency has set up a child center in Bantul to provide trauma counseling and recreation for children.

The World Health Organization is setting up a disease surveillance system to detect and control outbreaks of communicable diseases. It also will help organize vaccination campaigns against measles, a major killer of children.