At least 100 white hostages were killed by Katangan rebels during what may turn out to have been the worst massacre of Europeans in modern African history.

In one grisly mass slaying, 34 whites - men, women and a child - were herded into a small room of a villa and gunned down.

Their bodies, stacked two feet high, were still lying on the floor yesterday when Western journalists toured the gutted ruins of Kolwezi in the company of President Mobutu Sese Seko.

The death and destruction left behind by the rebels who controlled this town for six days were sickening.

One woman had put her fingers into her ears and apparently died screaming in a hail of bullets fired through a window.

A man was killed as he clutched a letter from his young son saying he hoped he would soon see his daddy.

There were unconfirmed reports of two other similar mass shootings, one involving 37 to 40 whites in the mess hall of the Gecamines Belgian-Zairian mining company. An undetermined number of other Europeans were executed in their homes and some others died in the fighting between the rebels and pro-government troops.

Two Americans were reported still missing and one may have been in the pile of bodies inside the villa, according to local sources. One American tourist and his Australian wife were reported safe after spending five days in rebel hands, Eleven missionaries also held as hostages were released unharmed.

Bill Starkey, an American working for the Morrison-Knudsen construction company was shot through the side by an AK-47 bullet and left for dead in a deserted part of the town. He managed to make his way to the hospital and was on his way to Kinshasa aboard a C141 transport Saturday night.

In addition, there were unconfirmed Zairian reports that about 60 Europeans taken prisoner when the rebels abandoned the town Friday had been executed on the road south to the Zambian border.

Refugees were coming out of the town by the hundreds yesterday and it appeared that practically all of the 2,000 Europeans were abandoning Kolwezi. Many said they had no intention of ever coming back.

With the flight of Europeans and some of the mines flooded with water, there were serious doubts that Kolwezi, the center of Zaire's copper industry would function again properly for months and that Zaire faces an economic crisis of major proportions.

The refugees were being flown by Zairian and French C130s to Kamina, 140 miles to the north, where five Boeing 707 Sabena Airline jets were waiting to fly them to Brussels. A few were being airlifted to the provincial capital, Lubumbashi.

The town of Kolwezi, described by the refugees as one of Zaire's finest, stood in a shambles with stores and homes pillaged, windows broken and walls pockmarked by bullets. Western correspondence who toured parts of the town counted between 20 and 30 bodies of blacks and whites still lying in the streets.

The slaughter which took place here was the worst anywhere in Africa since 1964, when a number of Europeans were killed by rebels after Belgian forces mounted a similar rescue operation in Kisangasi, then called Stanleyville. The Kelwezi massacre may well surpass that incident when the full story is known.

Almost all of the rebels pulled out of the town Friday as 800 French Foreign Legionnaires parachuted into the city and Belgian paratroopers landed to rescue the white hostages. There were still pockets of rebels, however, and Zairian Mirages, some manned by French pilots, were strafing a retreating column of rebels making its way toward the Zambian border presumably, on their way back into Angola.

Hundreds of Europeans were being brought by Belgian paratroopers to the airport from their homes where they said they had lived days and nights in terror and fear of death at the rebel hands.

Father Valerlus Messerich, 58, an American Franciscan missionary, told of being lined up and threatened at pistol point together with three others at his mission in the Zairian quarters of the city.

"You have a phoney and we are going to find it," they told him. Most missionaries here were thought by the rebels to have radio transmitters and to be informing Kinsahsa of what was happening here.

He said the rebels had been looking particlarly for Methodist Pastor Kenneth Enright, another American who by chance was away from Kolwezi when it fell last Saturday. A long-time resident in the area, Enright would almost certainly have been killed by the insurgents had they found him, Father Valerius said. His son was questioned but not harmed, he added.

Father Vel Rot Valerius said he and other members of his mission had been generally well treated during their captivity although they lost tape recorders, cameras and food.

Other French and Belgian refugees however, told tales of horror. One Belgian said his neighbour was killed, his throat slit and then after the rebels showed him to his wife they raped her. Others who resisted handing over food, their cars or even their waches were shot on the spot, several of the refugees said as they recounted incidents they had either seen or heard.

Some were held prisoner and told repeatedly to choose the hour they wanted to executed or were constantly threatened with death. One Belgian couple said the rebels had wanted to rape their nine-year-old daughter after taking all their food and valuables, but they were finally talked out of it.

Sarkey, the American who was shot said the rebels came tohis house on Thursday and took all kinds of strange objects, including golf balls and his glasses. They then ordered him to come with them and took him to a deseted quarter of town. There they told him to get out of the car and go away and when he did they fired upon him.Hit in the side, he jumped into a ditch and hid there until the rebels finally went away.

One young Italian woman saw her husband shot to death in front of their house after he made a remark that angered the rebels. Her father had spent five days as a hostage and had been threatened with death before paratroopers rescued him Friday.

The entire family was flying out to Lubumbashi yesterday, the woman choking back tears as her daughter sat on her lap. She told reporters she still had not told her child about her husband's death.

Most of the refugees interviewed by correpondents seem to feel they would not return again to Kolwezi because they feared a repitition of the rebel occupation and felt the situation was no longer safe. There were dozens of cars lined up at Kolwezi airport, some with keys in them - a clear sign that many had no intention of returning to this embattled town.