French and Belgian paratroopers joined forces yesterday to break the rebel hold on the besieged Zairian copper center of Kolwezi and rescue more than 2,000 Europeans held hostage there.

As the evacuation of foreigners got under way, military officials said sporadic fighting continued around Kolwezi, especially on its north side where paratroopers had surrounded 200 rebels holding out in a factory.

Diplomatic officials said at least 60 foreigners had been killed before the French and Belgian forces lifted the six-day siege of the town. Some of the evacuated foreigners arriving here in Zaire's capital last night said at least 100 Europeans were killed by the rebels.

Unofficial French and Belgian military sources estimated that 200 black civilians and military may have been killed during the siege. It appeared likely the final toll would be much higher for both whites and blacks.

Forty bodies were found in one spot near the cathedral, in the eastern part of Kolwezi. Refugees brought tales of terro and killings while Zaire's news agency and some of the refugees said the rebels raped wives and daughters of the victims.

Eighteen U.S. Air Force C141 transport planes and a giant C5A craft flew missions throughout the day supplying the French and Belgian forces in Zaire. The planes brought fuel, communications equipment and light vehicles.

(A Pentagon spokesman said that fewer than 100 U.S. military personnel were involved in the unloading operations at three Zaire airports, but none was in a combat role. A special team of the U.S. Air Force Military Airlift Command also was sent to Zaire to assist in the operation. Only Friday, White House press secretary Jody Powell said that "up to a dozen" American military personnel would be involved in the Zaire mission.)

Two Americans were among the first 550 persons evacuated from the town. French and Belgian troops talked to two other U.S. missionaries by radio and reported that they are alive and well.

[A State Department spokesman said 10 other Amercians in Kolwezi were not accounted for but there was no evidence that any of them were dead or injured.]

The rebel hold on Kolwezi was lifted when 1,000 Belgian troops parachuted overnight linked up yesterday with French Foreign Legion paratroopers who jumped into the town on Friday. Two hundred more French paratroopers were dropped into Kolwezi yesterday bringing France's total troop strength to 600.

The paratroopers, armed with detailed maps of Kolwezi, broke up into raiding parties and began mopping up pockets of rebel resistance. By nightfall, a French military spokesman in Paris, Col. Paul Cavarrot, said "our forces control the whole of the town.

The Angola-based rebels, who seized Kolwezi on May 12, were reportedly fleeing toward Zambian border, about 30 miles south of the town. A Shaba Province, formerly known as Katanga, was mounted in March 1977 but was repulsed by Zairian forces backed up by 1,500 Moroccan troops.

In this month's assault, the rebels including an unspecified number of Lunda tribesman living in exile in Angola, seized Kolwezi and its airport.

A French military spokesman said that up to 30 rebels were killed Friday in the French airport assault. One French soldier was killed and several others, including an officer, were injured. There were no reports of casualties among the Belgian troops.

The spokesman said that the French mission in Kolwezi "can be regarded as terminated," but there was no indication when the French and Belgians would be withdrawn.

The European refugees were being flown from Kolwezi to Kamina, then here to the capital which is 700 miles north of Shaba Province.

Belgian Premier Leo Tindemans said in Brussels that the rebels fleeing toward Zambia had taken along a number of hostages, including at least seven Frenchmen. He said Belgian troops have been ordered to attempt a rescue, suggesting that the paratroopers were in pursuit of the rebels.

The last census in Kolwezi showed about 2,500 Europeans, including 1,750 Belgians, 400 French, 200 Greeks, 100 Portuguese, 50 Italians, 14 Americans and 5 Swiss.

Yesterday's French-Belgian action appeared to end the rebel invasion of Shaba Province. Apart from Kolwezi, the rebels held no important town or center in he province.

Those rebels forces fleeing toward Zambia were reported to have taken with them captured vehicles, weapons and ammunition.

There have been various reports that Cuban and Soviet personnel had taken part in the rebel invasion of Shaba, but these could not be confirmed. The United States contends that the rebels were trained by Cuban officers in Angola and that they were equipped with Soviet weapons.