Tyson Fury says he has 'retired' but later says he's 'here to stay'

In a profanity-laced tweet Monday morning, heavyweight champion Tyson Fury initially said he is retiring from boxing before following up a few hours later by tweeting that he's "here to stay."

Fury's pair of tweets come three days after an ESPN report that he tested positive for cocaine from testing administered by the Las Vegas-based Voluntary Anti-Doping Association.

Fury had been set for an Oct. 29 rematch with former champion Wladimir Klitschko, but the English boxer pulled out of the fight last week for unspecified reasons, with promoter Mick Hennessy saying he had been "declared medically unfit to fight."

Fury submitted to a random urine test Sept. 22 in Lancaster, England, and the results came back positive for the substance benzoylecgonine, the central compound found in cocaine and the marker for a positive test for the banned substance, according to a letter obtained by ESPN's Dan Rafael.

The boxer is likely to be stripped of his heavyweight world title belts, and he faces a suspension for the positive drug test.