The sign language interpreter accused of using fake hand signals at Nelson Mandela's memorial has said he suffered a schizophrenic episode.

Thamsanqa Jantjie, 34, told South African media he "started hearing voices" and began hallucinating.

Deaf viewers at the memorial service said he was "signing rubbish", and complained he was a fraud.

Mr Mandela died last Thursday at the age of 95. His body is lying in state ahead of his burial on Sunday.

'Dangerous situation' Mr Jantjie said he worked for a company called SA Interpreters, where he is a senior interpreter.

During the memorial, he was employed to stand on the stage next to key speakers such as US President Barack Obama and Mr Mandela's grandchildren, translating their eulogies.

His performance was watched on television by millions of people worldwide.

But he said that during the event, he lost concentration because of voices in his head.

"There was nothing I could do. I was alone in a very dangerous situation," Mr Jantjie told Johannesburg's Star newspaper.

"I tried to control myself and not show the world what was going on. I am very sorry. It's the situation I found myself in."

But in a subsequent radio interview, he said he was happy with his performance.

"I've interpreted in many big events," he told Talk Radio 702. "I think I've been a champion of sign language."

Mr Jantjie's performance at the memorial provoked anger among South Africa's deaf community.

During the broadcast, Wilma Newhoudt-Druchen, the country's first deaf female MP, tweeted: "ANC-linked interpreter on the stage with dep president of ANC is signing rubbish. He cannot sign. Please get him off."

The ANC (African National Congress, the ruling party) was in charge of the memorial, along with the government.

It appears that Mr Jantjie has worked for the ANC before, as footage from two big ANC events last year show him signing on stage next to President Jacob Zuma.

The South Africa's Translators' Institute said there had been complaints over Mr Jantjie's work before, but the ruling party took no action.

The government is investigating what happened, but on Wednesday it said it "wishes to assure South Africans that we are clear in defending the rights and dignity of people with disabilities".