Accusations of mass doping worldwide made by German broadcaster ARD and the Sunday Times newspaper of Britain have plunged athletics into a new crisis less than three weeks before the world championships start in Beijing.
ARD and the Sunday Times newspaper said a "whistleblower" had handed over the IAAF database giving details of 12,000 blood tests from 5,000 competitors which revealed "extraordinary" levels of doping.
A large number of the "abnormal" results were from Russian athletes, said the reports. "A remarkable 80 percent of Russia's medal winners had recorded suspicious scores at some point in their careers," the Sunday Times said.
"The federation is currently making a close study of the (ARD film) materials," the statement said.
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"We are seriously concerned by the accusations over the anti-doping procedures in athletics along with the world athletics ruling body IAAF and the European athletics association."
ARD aired similar allegations of doping and corruption in Russian athletics in a separate investigation last year.
Athletics federation caretaker chief Vadim Zelichenok slammed the latest media claims as "biased material, which isn't based on facts".
Zelichenok said allegations that "up to 80 percent" of Russian athletes were doping sounded baseless.
"None of these cases have been proven. If this information was true the IAAF could never conceal it for almost 10 years," he said.
Yesterday, Russia's sports minister Vitaly Mutko also lashed out against the German broadcasters.
"Our former athletics federation bosses launched a legal action against those who made the first ARD film," Mutko said.