Bernard Madoff pleaded guilty on Thursday local time to orchestrating the biggest investment fraud in Wall Street history and was jailed to await a sentence that could keep him in prison for the rest of his life.

As some of his victims looked on in the courtroom, the former NASDAQ stock market chairman calmly described for 10 minutes a long-running, worldwide Ponzi scheme that he knew was criminal from the start but thought would end quickly.

"I am painfully aware that I have deeply hurt many, many people," including family, friends and associates, the grim-faced Madoff, 70, said before US Judge Denny Chin in Manhattan federal court. It was the first time he had spoken publicly of his crime.