Zaire May Close Its Rwanda Border : Africa: Government aims to head off a crisis near Bukavu similar to Goma. Sources say action could come Sunday.

Fearing that another Goma is about to consume their country, Zairian authorities threatened to close the border from Rwanda and to try to halt an ever-growing tide of refugees, the U.N. refugee office said Friday.

Already, about 136,000 Rwandans have moved across the Rusizi River from Rwanda into Bukavu, Zaire--with only 56,000 of them now contained in camps and the rest clogging this onetime resort city. Raw sewage is running in the streets, and diseases are spreading.

The Office of the U.N. High Commissioner for Refugees estimated that 200,000 more Rwandans are massed just across the border, with roads leading in this direction crowded with tens of thousands more. In total, perhaps 1 million people are within walking distance of this Zairian border town.

Goma, to the north, was besieged by perhaps 1 million Rwandan refugees last month in one of the greatest refugee catastrophes of modern times. At least 40,000 died there.

Exactly when the border would close remained uncertain Friday night. Jerry van Mourik, a worker with the refugee agency who was posted on the Rwandan side of the border, said “heavily armed” Zairian troops were moving into position on the opposite river bank with orders to block the two bridges at noon Sunday.

That would roughly coincide with a midnight Sunday withdrawal of French troops from the “safety zone” that they established for Hutus in that southwestern part of Rwanda.

“We have been notified that they are thinking of closing the border,” said Kris Janowski, spokesman for the U.N. agency. “They told us if they were headed for another Goma-type situation, they would close the border for security reasons.”

Relief officials said they were of mixed mind about a border closing. On one hand, the United Nations maintains that nations should not refuse refugees entry. On the other hand, Janowski said, “They’re much better off and safer in this case on the other side of the border.”

Some relief officials said they were worried about how Zaire could shut off the flow of such a great press of people, who already face what the United Nations has called “a psychosis of entrapment.”

Would the refugees take to the water and try to swim? Would the Zairian soldiers open fire?

At the border, relief officials said they counted 30 refugees a minute crossing the bridge, possibly 15,000 during the day, up from perhaps 6,000 Thursday.

The refugees, Hutus running from the possibility that Rwanda’s new Tutsi-dominated government may exact retribution for the slaughter of hundreds of thousands of Tutsis by Hutus, have been stampeded by the imminent departure of French troops who have been protecting them in southern Rwanda.

In Paris, a joint statement by President Francois Mitterrand and Prime Minister Edouard Balladur repeated that the French would stick to their scheduled departure at midnight Sunday.

Fears are likely to be heightened further, the Reuters news agency reported Friday, if word spreads of a report by some non-governmental groups saying they have uncovered evidence of Rwandan Patriotic Front (RPF) fighters massacring returning Hutu refugees.

The organizations--the Dutch disaster relief agency Novib, two Zairian groups and a Rwandan collective--say their report is based on interviews with four wounded Rwandans who say they survived mass executions in the Virunga wildlife park that separates northwest Rwanda from Zaire.

With nowhere else to go in this terraced, hillside city, refugees are jamming onto Bukavu’s traffic circles, packing into parks and gardens and into the front yards of local residents. Trees continue to fall all over town, and those too big to chop down are being whittled away at the base.

Water supply, traffic and sanitation are plainly at a crisis point, and certain to worsen.