Sara Jane Moore, the woman who attempted to assassinate President Gerald Ford in 1975, has said that she believed the US would change only through a violent revolution.

Moore, who spent 32 years in prison for firing a shot that missed the president's head by several feet, admitted in an interview that she now realises that her actions were "wrong ... a serious error".

At the time, the 45-year-old divorced mother had become immersed in leftist groups in California that fed her feeling of alienation.

Moore was sentenced to life in prison but released on parole in December 2007. She has lived in an undisclosed location since then.

It was during the long years in jail, six of which were spent in solitary confinement, that she "gradually ... began to realise that I had let myself be used. ... I definitely think that it was wrong. I think I was misled. I think I was mistaken. I think I made a serious error."