Ceremonies in memory of 49 people who died during attacks by South African forces on anti-apartheid activists in Lesotho in the 1980s will be held Friday and Saturday in the capital Maseru.
A 1982 raid on Maseru by the South African National Defence Force (SANDF) killed 40, including five women and two children.
The December 9 raid was described by then SANDF chief, General Constand Viljoen, as a pre-emptive strike targeting 12 members of the African National Congress (ANC), which has been in power in South Africa since apartheid ended in 1994.
Nine others perished in another raid in 1985.
The governments of South Africa and Lesotho along with a memorial group, the Freedom Park Trust of South Africa, are jointly participating in the commemoration that will begin with a cleansing and healing ceremony on Friday.
Lesotho and South African traditional healers will preside over the slaughter of sacrificial animals, which will be presented to the ancestors.
Wally Serote, the executive chairman of the Freedom Park Trust, said the two-day commemoration was a "symbolic cleansing and healing of the wounds inflicted by the injustices of the past."
He said "soil from the graves of people who fell during conflict in Lesotho will be collected" to form part of a memorial in Pretoria, which will commemorate "those who died in the conflict events that mark South Africas history."
On Saturday, there will be a religious ceremony attended by Roman Catholic, Anglican and Evangelical priests. South African Defence Minister Mosiuoa Lekota and his Lesotho counterpart Mohlabi Tsekoa will represent their governments.
The ANC, Africa's oldest liberation movement, was banned under apartheid and operated from exile in London, Moscow and several African nations during white minority rule.
Between 1975 and 1980 six nations -- Angola, Botswana, Mozambique, Tanzania, Zambia and Zimbabwe -- teamed up to form a body dubbed the Frontline States to aid the liberation movements in South Africa and Namibia.
The price they paid was dear, ranging from military raids to covert support to rebel movements in Angola and Mozambique.