Renown track coach Alberto Salazar has received a four-year ban by the U.S. Anti-Doping Agency (USADA) for doping violations.
USADA announced on Monday Salazar is being sanctioned "for orchestrating and facilitating prohibited doping conduct while acting as head coach of the Nike Oregon Project (NOP)" which is a training camp set up to develop athletes.
Endocrinologist Jeffrey Brown was also banned. He worked as a consultant for the NOP.
"I am shocked by the outcome today," Salazar said on the NOP website. "I have always ensured the WADA code is strictly followed. The Oregon Project has never and will never permit doping."
"I will appeal and and look forward to this unfair and protracted process reaching the conclusion I know to be true."
In its statement USADA said, an arbitration panel found that Salazar and Brown "trafficked testosterone, administered a prohibited IV infusion, and engaged in tampering to attempt to prevent relevant information about their conduct from being learned by USADA".
Salazar has denied any wrongdoing.
The 61-year-old trained four-time Olympic champion Mo Farah and 2012 Olympic silver medallist Galen Rupp. Both have denied any involvement in doping.
Farah stopped working with Salazar in 2017.
"I'm relieved that USADA has, after four years, completed their investigation into Alberto Salazar," Farah said in a statement on Tuesday. "I left the Nike Oregon Project in 2017 but I've always said, I have no tolerance for anyone who breaks the rules or crosses a line;. A ruling has been made and I'm glad there has finally been a conclusion.
USADA's announcement marked the end of a four-year investigation in which the organisation interviewed 30 witnesses and analysed more than 2,000 exhibits and nearly 5,800 pages of transcript.
In the news release no athletes were cited for wrongdoing.
"The athletes in these cases found the courage to speak out and ultimately exposed the truth," said USADA's Chief Executive Officer Travis T. Tygart.
"While acting in connection with the Nike Oregon Project, Mr. Salazar and Dr. Brown demonstrated that winning was more important than the health and wellbeing of the athletes they were sworn to protect."
In a response to the suspension, Salazar criticised "my athletes and I endured unjust, unehtical and highly damaging treatment from USADA".
"This is demonstrated by the misleading statement released by Travis Tygart stating that we put winning ahead of athlete safety."
Salazar has won the New York City Marathon three times and the Boston Marathon once. He was involved with the Nike Oregon Project from its beginning in 2001.