THOUSANDS DISPLACED BY FIGHTING IN ZAIRE.

Byline: James C. McKinley Jr. The New York Times

A human disaster looms in eastern Zaire.

Fighting between the Zairian army and Tutsi rebels Friday entered a seventh day, crippling efforts by relief agencies to reach tens of thousands of refugees and threatening to touch off a regional war, diplomats and officials said.

At least 120,000 Hutu refugees who fled 12 camps in Uvira, Zaire, are hiding in the hills and banana plantations between Lake Kivu and Lake Tanganyika, foraging for food and relying on unclean water, U.N. officials said.

At least 80,000 more have reached camps near the Zairian regional capital, Bukavu, about 60 miles to the north, but the fighting has cut off food supply routes, and there is only enough food for about three days, officials said.

``That's just a pure breeding ground for epidemics and malnutrition,'' said Brenda Barton, a spokeswoman for the World Food Program in Nairobi, Kenya. ``We have got to be moving supplies.''

At the same time, Zairian Tutsi have crossed into Rwanda, telling stories of being harassed, beaten or jailed by government soldiers. They accuse the Zairian military of a program against Tutsi that they say is reminiscent of the 1994 genocide in Rwanda.

The conflict appeared to be on the brink of bubbling over into a border war as United States and European diplomats struggled Friday to arrange peace talks between the Zairian and Rwandan leaders.

In Brussels Zairian Prime Minister Kengo wa Dondo accused Rwandan troops, who are predominantly Tutsi, of invading eastern Zaire and fighting alongside fellow Tutsi in Zaire. Rwanda has denied aiding the Zairian Tutsi but has supported their cause and has accused Zaire of persecuting Tutsi.

``This could draw these two countries into war,'' said a diplomat in Kigali, the capital of Rwanda.

Heavy artillery fire was reported Friday afternoon around Uvira, where clashes Sunday prompted the Hutu refugees from Rwanda and Burundi to flee their camps and head toward Bukavu. But details about the fighting remained hazy, with the Zairian government barring most journalists from the country.

The fighting is the latest among increasingly violent conflicts that began two years ago, when more than a million Hutu flooded across the border from Rwanda just ahead of advancing Tutsi-led fighters.

Many Hutu refugees were former militiamen and soldiers who took part in the massacres of at least 500,000 Tutsis in 1994, and they brought with them a virulent hatred for Tutsi.

Since then, hundreds have been killed in Rwanda in cross-border attacks that are thought to have originated in the Hutu camps in Zaire, which also house Hutu rebels fighting the military government in Burundi.

Last spring the Hutu militias in Zairian camps near Goma, at the north end of Lake Kivu, began stirring up anti-Tutsi sentiment in Masisi and Rutshiro, about 40 miles to the north. Hundreds of Tutsi were killed, and the violence forced about 65,000 people to flee to Rwanda.

In September, several politicians in South Kivu province in Zaire, including the governor, Kimba wa Lumona, and his deputy, Lwasi Ngabo Lwabanji, began a similar campaign against the Banyamulenge, ethnic Tutsi who have lived in the highlands above Lake Tanganyika since the 17th century, Tutsi refugees said.

The army stepped up its harassment of Tutsi landowners. Finally, on Oct. 8, Lwabanji ordered the Tutsi residents to leave the country within a week or be treated as rebels.