Sponsor confirms it has terminated Armstrong's deal'Nike does not condone the use of illegal drugs'

Nike has severed its connections with Lance Armstrong, finally acknowledging the "seemingly insurmountable" evidence that that the seven-times Tour de France winner was a drugs cheat.

In a near-simultaneous statement, Armstrong said he would relinquish his position as chairman of Livestrong, the cancer charity he founded, in order to "spare the foundation any negative effects" after a damning report by the United States Anti-Doping Agency (Usada), which concluded he ran a sophisticated doping ring for years.

Armstrong's decision to step down from Livestrong allowed Nike to continue to support the initiative. In the US, 98 products bearing the Livestrong name are sold by Nike.

Nike – which initially indicated that it would stand by Armstrong – said in a statement it had been misled by Armstrong and did not "condone the use of illegal performance-enhancing drugs".

The full statement said: "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. Nike does not condone the use of illegal performance enhancing drugs in any manner.

"Nike plans to continue support of the Livestrong initiatives created to unite, inspire and empower people affected by cancer."

Armstrong has been dogged for years by allegations that he cheated his way to his Tour de France titles, while he was lead cyclist with his US Postal Service and Discovery Channel teams. Last week, Usada released a 1,000-page dossier which concluded that what had transpired amounted to "the most sophisticated, professionalised and successful doping programme that sport has ever seen".

Despite strongly denying the doping allegations, Armstrong elected not to fight Usada's claims, saying he thought the process was unfair.

The loss of the Nike deal will come as a financial blow, but stepping down from Livestrong is likely to be more personally damaging. Armstrong, a cancer survivor, set up the foundation in 1997, in order to help inspire others battling the illness. His inspiring story, of recovering from testicular cancer that had spread to his lungs and brain and then winning the world's most famous cycle race, helped the foundation grow from a small operation in Texas into one of the most popular charities in the US.

The cyclist insisted he was drug free at a time when doping was rampant in professional cycling. In 2004, the foundation introduced yellow "Livestrong" bracelets; more than 80 million were sold, creating a global symbol for cancer awareness and survival.

Armstrong, who was not paid a salary as chairman of the Lance Armstrong Foundation, will remain on its board, but his duties will be handed to the vice chairman, Jeff Garvey.

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

As chairman, Armstrong did not run the foundation's day-to-day operations, which are handled by the Livestrong president and chief executive, Doug Ulman. Ulman had said that Armstrong's leadership role would not change.

Armstrong's statement said he would remain a visible advocate for cancer issues. He is expected to speak at Friday night's 15th-anniversary gala for Livestrong in Austin, Texas.

"My family and I have devoted our lives to the work of the foundation and that will not change," Armstrong said. "We plan to continue our service to the foundation and the cancer community. We will remain active advocates for cancer survivors and engaged supporters of the fight against cancer."