Moore, 77, had served 32 years of a life sentence when she was released from the federal prison in Dublin, east of San Francisco, the Federal Bureau of Prisons said.

Bureau spokeswoman Felicia Ponce said she had no details on why Moore was released.

Moore was 40 feet away from Ford outside a hotel in San Francisco when she fired a shot at him on September 22, 1975.

As she raised her .38-caliber revolver and pulled the trigger, Oliver Sipple, a disabled former Marine standing next to her, pushed up her arm. The bullet flew over Ford's head by several feet.

In recent interviews, Moore said she regretted her actions, saying she was blinded by her radical political views.

"I am very glad I did not succeed. I know now that I was wrong to try," Moore said a year ago in an interview with KGO-TV.

Just 17 days before Moore tried to kill the president, Ford survived an attempt on his life in Sacramento by Lynette "Squeaky" Fromme, a follower of Charles Manson.

Moore said that she was convinced at the time that the government had declared war on the left.