American 100-meter record holder Tyson Gay has tested positive for a banned substance and says he will pull out of the world championships next month in Moscow.

Gay isn’t revealing the substance, but he says he was notified by the U.S. Anti-Doping Agency on Friday that a sample came back positive from an out-of-competition test May 16. He says he will have his “B” sample tested soon.

The 30-year-old Gay fought back sobs in a phone conversation Sunday from Amsterdam, saying: “I don’t have a sabotage story. … I basically put my trust in someone and was let down.”