The shocking video Afrikaner Blood by Elles van Gelder and Ilvy Njiokiktjien from the Netherlands has won first prize in the World Press Photo 2012 multimedia contest. The piece follows young white South African teenagers who attend a holiday camp set up by a right-wing racist group.

According to the documentary's producers, the little-known group Kommandokorps is teaching Afrikaner boys "to eschew Nelson Mandela's vision of a multicultural rainbow nation." Ms Van Gelder told the BBC: "A lot of people are shocked that this exists in South Africa - the images almost look like they were taken in the past."

"These kids are basically brainwashed. They come into the camp, they say they believe in the rainbow nation, they say they have black South African friends. When they get out of the camp they don't want to be South Africans any more and really believe that black South Africans are their enemies," said Ms Van Gelder.

The group is led by Franz Jooste (centre) who was an army major during the era of white minority rule which ended in 1994 with the election of Nelson Mandela as the country's first black president. Ms Van Gelder says Mr Jooste is trying to breed a new generation of racists because his organisation only has the support of a tiny minority.

"I am not ashamed to say I am a racist. In South Africa you can only be one of two things: Either you are blind or you are a racist," he says. After decades of government-enforced racial divisions, experts say black and white South Africans generally get on relatively well. However, some white people complain about the high crime rate, in particular the killing of white farmers. Equally, some black people say they remain economically marginalised.

According to Ms Van Gelder, Mr Jooste "believes white South Africans should have their own nation and that they are too different from the black population in South Africa to live together". The mainly white Freedom Front has condemned the camps. "The fact that these camps indoctrinate young boys to hate black people is not a solution to the current problems of South Africa," its youth leader Wouter Wessells told the BBC. "Not all Afrikaners are like that."

The multimedia production combines Ms Van Gelder's videos with Ms Njiokiktjien's photographs. "Because the statements of the leader of this Kommandokorps are so harsh and so intriguing in many ways, the stills help to get some rest in the documentary and you can really listen to what he says," the filmmaker explained.

"We are Afrikaners. We are our own people. This is how much disrespect we have for that thing," the ex-army major says as the documentary shows images of boys stamping on South Africa's flag.

"It takes me a one-hour lecture to change his mind. Then he knows he is no longer part of the rainbow nation. He is part of a different nation with a very proud history," Mr Jooste boasts. Kommandokorps claims to have trained about 1,500 people - from a total white population of 4.6 million. The police do not publish data on the numbers of racist attacks but the South African Institute of Race Relations (SAIRR) says the number of media reports of racist incidents is decreasing.

As he arrives at the camp, Riaan, 18, says: "South Africa is a rainbow nation because there are diverse ethnic groups in this country." After the training he has changed his views: "I have Afrikaner blood in my veins. I don't want to be a South African. I don't want to be associated with the rainbow nation."

"I don't like racism because people tend to get angry at one another and they maybe hit one another," a boy of 16 says. "This camp promotes racism but not bad racism," another one adds. Lucy Holborn from the SAIRR says many people were shocked by the video but this soon died down as people realised it represents just a small minority of the white population.

"When I was in the ground it was tough. I was in pain... I want to prove that I can," says one of the boys. Another, crying, added: "I don't want to disappoint my dad but I can't do this."