Former President Thabo Mbeki says former deputy president FW De Klerk told him that he was not aware of the United Nations’ convention that declared apartheid a crime against humanity.

This comes after De Klerk disputed that the racially oppressive system of apartheid was a crime against humanity during an SABC interview to mark the unbanning of apartheid in 1990.

Mbeki says during his conversation with De Klerk, the former statesman apologised.

WATCH: Mbeki weighs in on De Klerk apartheid utterances

In a statement, the De Klerk Foundation claims that the United Nation’s classification of apartheid as a crime against humanity formed part of an agenda by the Soviet Union and the African National Congress along with its allies to stigmatize white South Africans. The statement also sought to justify and reason as to why apartheid was not a crime against humanity.

READ: De Klerk Foundation’s statement sought to justify why apartheid was not a crime against humanity.

WATCH: In the clip below, De Klerk disputes the notion that apartheid is/was a crime against humanity.

The Council of Churches says the remarks made by De Klerk and his foundation go against the values for which he was awarded the Nobel Peace Prize.

In 1993, de Klerk was jointly awarded the Nobel Peace Prize alongside former President Nelson Mandela for their work in ending apartheid.

WATCH: The South African Council of Churches is calling on the De Klerk Foundation to retract and apologise:

De Klerk served as a deputy president during the Mandela era and also was the last president of Apartheid South Africa.

Meanwhile, the South African Human Rights Commission also weighed in, saying that it would be difficult to charge the former statesman over his utterances.

The commission’s CEO Tseliso Thipanyane says, “Since 1994, we’ve said let us move from the past to the future and also remember the ANC itself took a number of National Party members – Mr Marthinus Van Schalkwyk became a minister in the new South Africa. So, we can’t focus on one person and not focus on others – there are a number of people who were in the previous apartheid government and became officials in the new South Africa.”