RIO DE JANEIRO, Nov. 27 (Xinhua) -- Brazilian Olympic boxing medal hopeful Clelia Costa has tested positive to a banned substance, local officials said on Friday.

Costa was found to have the masking agent furosemide in a urine sample taken in September, Brazil's Boxing Confederation (CBB) said in a statement.

Until Friday, she was one of Brazil's leading hopes for next year's Olympics in Rio de Janeiro, having won bronze in the 51kg division at last year's World Championships.

Under Brazil's anti-doping rules, Costa has been automatically suspended from all competition for at least 180 days.

Brazil's former 50m Olympic freestyle swimming champion Cesar Cielo tested positive to the same substance in 2011 but was absolved after blaming a contaminated supplement.