Children will be hit hardest by deadly dysentery spreading among more than a million Rwandan refugees jammed into wretched camps along Zaire's eastern border, a relief group said Tuesday.

Only Monday, the U.N. High Commissioner for Refugees visited the camps and said she saw reason for hope, despite the misery all around her."Dysentery has overtaken cholera" as the main disease afflicting refugees, said Samantha Bolton of the relief group Doctors Without Borders. She said 76 dysentery patients were treated at one of her agency's clinics Monday, compared with 33 cases of chol-era.

"This is going to strike kids more than adults," Bolton said. "It's going to be very expensive and time-consuming to treat, and you're going to see an upsurge in deaths."

Cholera and dysentery are both spread by fecal contamination of food and water. Cholera is treated with an infusion of liquids and minerals to replace those lost by the body through vomiting and diarrhea. Dysentery requires five days of costly antibiotics.

Ray Wilkinson, spokesman for the U.N.'s refugee agency, said Tuesday the number of reported deaths in the camps had fallen to an estimated 800 to 900 daily, down from 1,800 to 2,000 early last week.

"That figure undoubtedly will go up when the dysentery movesup in scope," he said.

The U.N. has appealed for $434 million in donations to help the refugees, and representatives from about 40 countries were meeting in Geneva Tuesday to pledge funds.

Sadako Ogata, the U.N. High Commissioner for Refugees, told the meeting the agency faced a cash shortfall of $65 million. Despite a huge international aid effort, she said, the agency desperately needs help improving sanitation, camp and road fa-cil-i-ties.

Ogata made her first visit to the camps Monday, then flew to Ge-ne-va.

In Goma, where death and suffering surrounded her, she was cheered to see cholera victims saved by Red Cross and volunteer doctors, U.S. planes ferrying in water tankers, and engineers bulldozing roads so they could serve more people.

"Things are bad but they're going to get better," Ogata said Mon-day.

In Geneva Tuesday, Sylvana Foa, a spokeswoman for the High Commissioner's office, said the arrival of more bulldozers to bury the dead in mass graves has helped to control the spread of disease.

"There were no bodies in the camp yesterday and that has eliminated a major health problem," she said.

The U.N. Children's Fund on Monday estimated 50,000 people have died in the camps in the past two weeks, more than twice the High Commissioner's figure of 20,000.

U.S. military efforts to increase the flow of clean water to the camps gained momentum. Transports brought the first of three 3,000-gallon U.S. water tankers, and nine tankers were expected from Finland.

U.S. Army engineers bulldozed two paths through Kibumba, 20 miles north of Goma, where the crush of refugees has slowed traffic to a crawl. The paths will make it easier for U.N. trucks to carry water there from an American water purification site in Goma.

On television news shows in the United States Tuesday morning, Defense Secretary William Perry said American troops will not be part of a 4,100-member U.N. peacekeeping mission authorized for Rwanda. The U.S. military will only be involved in refugee relief operations, he said.

"The United States will provide logistic support for the peacekeeping operation, but we're not going to provide troops for it," he said.

The United States has 1,200 troops in the region now and could have as many as 2,000, he said.

In Kigali, the Rwandan capital, more than 100 U.S. military personnel worked nonstop to open the airport 24 hours a day to relief flights and, in the process, ease the aid logjam at Goma's tiny airport.