MOSCOW, Nov. 8 (Xinhua) -- The Russian Investigative Committee contested Wednesday the report of the World Anti-Doping Agency (WADA) alleging widespread doping in Russia, which threatened the country's participation in 2018 Winter Olympics.
"The investigation had obtained data that WADA lacked any evidence of Russia's guilt in the mass use of doping by athletes," it said in a statement.
The investigation by the committee which started at the end of last year has overturned "the arguments of independent WADA expert McLaren about the substitution of positive doping samples of Russian athletes for negative at the Sochi Winter Olympics in the Sochi Anti-Doping Laboratory and the existence in Russia of a certain state doping program," the statement said.
The investigators questioned more than 700 athletes, coaches, medical workers of the Russian national teams, employees of Russian Sports Federations, the Russian National Teams Training Center, the Russian Anti-Doping Agency RUSADA and the Russian Anti-Doping Center, it said.
None of them confirmed the existence of a certain doping program. If there were any violations of the anti-doping rules, they were of a "purely individual nature", the committee said.
The investigators also questioned construction workers, security guards and maintenance personnel who worked during the Sochi Olympics and inspected various premises used as an anti-doping laboratory without finding proof of the WADA allegations.
Last year, an independent WADA commission headed by Professor Richard McLaren released a report accusing Russia of state-sponsored doping programs to illegally boost Russian athletes' performances.
The report was largely based on the testimony of the former head of a Moscow anti-doping lab Grigory Rodchenkov, who fled to the United States at the end of 2015, becoming an informant for WADA.
The scandal prevented a large number of Russian athletes and officials from participating in the 2016 Rio Olympics and Paralympics and raised queries about the participation of the Russian national team in the 2018 Winter Olympic Games in South Korea's PyeongChang.
In September, a Moscow court has issued a warrant for the arrest of Rodchenkov in absentia.
The Investigative Committee said in its Wednesday's statement that it had gathered enough evidence of Rodchenkov distributing drugs, subsequently identified as doping, and destroying the doping tests of Russian athletes.
The Investigative Committee decided to put Rodchenkov on the international wanted list and to demand his extradition from the United States, it said.