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AIGLE, Switzerland (AP) - Russian track cyclist Valery Kaykov has been suspended after testing positive for a black-market drug that the World Anti-Doping Agency issued a health warning about last month.

The International Cycling Union says Valery Kaykov, a European Championships silver medalist last year, tested positive in an out-of-competition sample for the substance WADA called "GW501516."

The UCI says his sample was given on March 17, four days before WADA urged athletes not to use the endurance-boosting substance that had toxic side effects in pre-clinical studies.

Kaykov is provisionally suspended from competition while the Russian cycling federation prosecutes a disciplinary case.

The UCI says Kaykov can request to attend the analysis of his backup sample. The original test was done by the WADA-accredited laboratory in Cologne, Germany.

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