From Katanga 1960-63: Mercenaries, Spies and the African Nation that Waged War on the World, by Christopher Othen (History Press, 2015), Kindle Loc. ~4646:
On 21 January, Tshombe signed an official declaration that the secession had ended. Along with Munongo, Yav, Muke, Kimba and Kibwe, he dined with UN officials in Kolwezi.
‘Atmosphere friendly’, a UN man telegraphed to Léopoldville, ‘but throughout our conversation we felt Tshombe and Cabinet are extremely REPEAT extremely bitter about Europeans in general, Belgians in particular.’
Munongo publically renounced any further resistance or guerrilla warfare. Tshombe announced that he was prepared to work with Léopoldville to solve the Congo crisis. On Tuesday, Joseph Ileo arrived in Elisabethville to take over the province for the central government and Tshombe returned to the presidential palace to await his fate. UN and Congolese flags flew over Katangese towns.
Since 1960, the UN had lost 135 men in the Congo, including fourteen Irish soldiers (nine of those killed by Baluba at Niemba), thirty-nine Indian, nineteen Swedish and forty-seven Ghanaian soldiers. Only around half the total died at the hands of the Katangese. Baluba, the Léopoldville ANC and Gizenga’s men killed the rest. On the other side, perhaps only thirty-two mercenaries were killed in action during the secession. No one counted dead gendarmes, but they must have been in the low thousands. Civilian deaths on all sides amounted to at least 10,000 and were probably much higher.
In Léopoldville’s boulevard Albert, 600 students chanted ‘Tshombe to the gallows!’ Others stormed the British embassy as Congolese police sat in their jeeps and laughed. Léopoldville agreed an amnesty for Tshombe and his men. The UN soon discovered that the gendarmes were only prepared to surrender if no ANC men were in the area. Kasa-Vubu gave a speech:
Officers, non-commissioned officers and men of the former Katangese Gendarmerie, in addressing myself particularly to you this evening, I do so on behalf of the entire country, the entire nation, to congratulate you and pay you a tribute for your patriotism because it was thanks to your understanding and to your refusal to use the murderous weapons placed in your hands by foreigners that the secession was ended, without too great a loss of human life or shedding of blood.
On 25 January, the last of the Katangese armed forces crossed the border into Portuguese Angola. They would return, but to fight for a different cause and against a different enemy. Katanga had failed as a country.