Nike broke with Lance Armstrong Wednesday over his alleged doping and accused the disgraced cycling star of deceiving his sponsor for years.

"Due to the seemingly insurmountable evidence that Lance Armstrong participated in doping and misled Nike for more than a decade, it is with great sadness that we have terminated our contract with him," the sporting goods giant said in a brief statement.

Earlier, Armstrong himself announced he was stepping down as chairman of his cancer-fighting charity Livestrong.

He said he did not want the controversy over his cycling career to distract the foundation from its mission of helping people with cancer.

"I have had the great honor of serving as this foundation's chairman for the last five years and its mission and success are my top priorities. Today therefore, to spare the foundation any negative effects as a result of controversy surrounding my cycling career, I will conclude my chairmanship," Armstrong said in a statement on the foundation's website.