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Nike said in a statement Wednesday that it is terminating its contract with Lance Armstrong due to "seemingly insurmountable evidence" the Tour de France champion participated in doping and misled the company for more than a decade, the company said in a statement.

The company's decision was announced the same day Armstrong said he was stepping down as chairman of his Livestrong cancer-fighting charity so the group can focus on its mission instead of its founder's problems.

Nike, for its part, said it will continue to support the Livestrong initiatives.

Anheuser-Busch, the brewer of Budweiser, also said it would continue to support Armstrong's charity, but would not renew its relationship with the former cyclist, Reuters reported.

The Wall Street Journal reported that RadioShack Corp. ended its relationship with Armstrong, after the U.S. Anti-Doping Agency's report last week detailing his use of performance-enhancing drugs.

"I can say that RadioShack has no current obligations with Lance Armstrong," said a spokesman for RadioShack in a statement., The Journal reported.

Armstrong's move came a week after the U.S. Anti-Doping Agency released a massive report detailing allegations of widespread doping by Armstrong and his teams when he won the Tour de France seven consecutive times from 1999 to 2005. The document's purpose was to show why USADA has banned him from cycling for life and ordered 14 years of his career results erased -- including those Tour titles. It contains sworn statements from 26 witnesses, including 11 former teammates.

Armstrong, who was not paid a salary as chairman of the Lance Armstrong Foundation, will remain on its 15-member board. His duties leading the board will be turned over to vice chairman Jeff Garvey, who was founding chairman in 1997.

"This organization, its mission and its supporters are incredibly dear to my heart," Armstrong said in a statement obtained by The Associated Press. "Today therefore, to spare the foundation any negative effects as a result of controversy surrounding my cycling career, I will conclude my chairmanship."

The Associated Press contributed to this report