Frederik Willem De Klerk, the man known for releasing Nelson Mandela from prison and ending apartheid.

South Africa’s last apartheid president, Frederik Willem De Klerk, has withdrawn from a U.S. seminar about minority rights.

According to his foundation, he withdrew because he did not want to embarrass himself or his hosts in the current charged racial climate.

De Klerk, who was the head of South Africa’s white minority government until 1994, was scheduled to speak on issues such as minority rights, racism and the rule of law at an American Bar Association (ABA) virtual event.

But his participation unleashed a barrage of criticism from South African opposition parties and activists, who called on ABA to cancel De Klerk’s attendance given his role in the apartheid-era security apparatus.

“The allegation that De Klerk was involved in gross violations of human rights is baseless,’’ the F.W. De Klerk foundation said in a statement.

“However, it appears unacceptable in the current super-heated racial climate that any leader from South Africa’s troubled past should be permitted to retain the slightest vestige of honour,’’ it said.

ABA confirmed De Klerk would no longer speak at the event.

De Klerk’s foundation defended his legacy of helping South Africa’s transition from white minority rule to non-racial constitutional democracy and for being the only world leader to dismantle an existing nuclear arsenal.

But, almost 30 years after apartheid’s demise, De Klerk’s role remains highly contested in South Africa, one of the world’s most unequal societies where class and race issues constantly bubbling under the surface.