Estonia's two-time Olympic nordic skiing champion Andrus Veerpalu said Tuesday he would turn to the Court of Arbitration for Sport (CAS) to appeal a decision by world skiing body FIS confirming and extending a doping ban. Veerpalu is challenging the decision even though it is a symbolic punishment given that he retired in February this year. "The FIS did not take into account the arguments presented by our team and our scientists and we will go on to prove I am not guilty," the former cross-country star Veerpalu said in a statement issued by the Estonian Ski Association. With two golds and a silver, Veerpalu -- who is also a two-time world champion -- ties women's cross-country skier Kristina Smigun-Vaehi as Estonia's most successful Olympian. "One more sportsman is currently disputing that test. There is no reason to stop now because I am convinced I have not done anything wrong," Veerpalu added. FIS said on Monday that its ruling on Veerpalu's positive doping test results will stand and extended his two-year competition ban to three years. In April, it emerged that the 40-year-old Veerpalu had failed a doping test on the eve of his retirement. A February 14 World Anti-Doping Agency test had detected a higher-than-permitted level of growth hormone. Another test confirmed the result in April. The sample was taken out-of-competition on January 29 in Veerpalu's hometown Otepaa in southern Estonia. On February 23 Veerpalu announced he was hanging up his skis. At the time, he said he made his mind up after a virus forced him to skip the Nordic World Ski Championships in Norway and Veerpalu has repeatedly denied ever having used a banned substance. Veerpalu won Olympic gold and silver in Salt Lake City in 2002 and gold in Turin in 2006. He is an idol in this nation of 1.3 million, which rejoined the global sporting fold after five decades of Soviet rule ended in 1991, and Veerpalu has drawn strong public support. The Facebook site, created in spring and named, in Estonian, as "We believe Andrus Veerpalu" had 67,023 members on Tuesday.