The sign-language interpreter accused of using fake hand gestures at Nelson Mandela's memorial service told a Johannesburg radio station he is schizophrenic and was hallucinating during the ceremony.

“I’m currently a patient receiving treatment in schizophrenia,” Thamsanqa Jantjie told Talk Radio 702, according to The Wall Street Journal.

He said that he was certified to translate English into sign language, but that during the ceremony slipped into an altered state and saw angels entering the stadium. In a separate interview with The Associated Press, Jantjie admitted said there were instances where he had become violent during a schizophrenic episode.

“I don’t know the attack of this problem, how will it come,” he told the Associated Press. "Sometimes I get violent on that place. Sometimes I will see things chasing me.”

The revelations are likely to raise questions the security of President Obama, who spoke just a feet away from Jantjie.

On Wednesday, White House spokesman Josh Earnest said he was not aware of any security concerns related to the president's speech.

But Earnest said he was disappointed the controversy had overshadowed the Mandela service.

"It’s a shame that you had a service that was dedicated to honoring the life and celebrating the legacy of one of the great leaders of the 20th century has gotten distracted by this and a couple of other issues that are far less important than the legacy of Nelson Mandela," Earnest said.

The Secret Service did not immediately respond to a request for comment.

The African National Congress — the political party that Mandela lead — said it had used Jantjie to translate before and was unaware of his apparent illness.

“Until yesterday, the African National Congress had not been aware of any complaints regarding the quality of services, qualifications or reported illnesses of Mr. Jantjie,” the party said, according to the Journal.