Gasquet said in a statement Sunday that the "B'' sample from the tournament in Key Biscayne, Florida, confirmed the result of the "A'' sample taken the same day.
"Given the complexity of this dossier, I am gathering together proof of my innocence and I will choose an appropriate moment to express myself,'' Gasquet said.
The Web site of sports daily L'Equipe had reported Saturday that traces of the banned drug were found in the 22-year-old Gasquet's urine sample at the Sony Ericsson Open, where he pulled out after the first round.
The French tennis federation called the report "very surprising'' and said Sunday it would wait for official confirmation before taking any action against him.
Gasquet cited a right shoulder injury when he withdrew before his second-round match against Albert Montanes of Spain. He could face a two-year ban.
The FFT said in a statement that it "would be very sad for Richard Gasquet himself, for tennis in general, for French tennis in particular, whose image would be dented'' if the positive test was officially confirmed.
It added that it will take no action until it has been notified to do so by the governing body of tennis and the World Anti-Doping Agency.
"The FFT will follow developments in this affair with the greatest attention, will avoid passing a hasty moral judgment and take care to leave the player to organize his defense,'' the FFT said. "If the facts are nevertheless proven, it would be particularly regrettable in view of all the efforts the FFT makes with players about (drug) prevention.''
Gasquet reached the semifinals at Wimbledon in 2007, but has struggled with his form since then and is currently ranked 23rd.
