Venezuelan rider Miguel Ubeto, who joined Lampre this year, has returned a sample that showed traces of GW1516, also known as GW501516, following an out-of-competition test taken on April 16, the UCI said in a statement yesterday.

"The provisional suspension of Mr. Miguel Ubeto Aponte remains in force until a hearing panel convened by the Venezuelan Cycling Federation determines whether he has committed an anti-doping rule violation," the UCI said.

Ubeto can ask to have the B sample tested.

WADA issued a warning about the once developmental drug in March, saying it had been withdrawn from research but was available on the black market and contained "serious toxicities".

A Lampre team statement said: "Ubeto Aponte had not yet made his debut with the team jersey, due to an injury.

"While waiting to receive information and any clarification from Ubeto Aponte and evaluate additional measures, the team reiterates its support for all efforts to make cycling cleaner and credible, severely condemning any behaviour violating anti-doping rules."

Today, the Lampre team has released a public statement by the rider in which he assumes sole responsibility for any wrongdoing.

“I, Miguel Armando Ubeto Aponte, by the means of this letter, would like to explain the situation linked to the adverse analytical finding of the substance GW1516, that was detected during an out of competition control, taking on all the culpability for what happened and apologizing to Team LAMPRE-MERIDA.

In January 2013, I suffered an injury (broken humerus) because of a crash in Vuelta al Tachira and I underwent surgery in Atias Clinic in Caracas. The clinic doctors suggested a therapy that called for the consumption of medicines including the substance GW1516. The documents that certify this suggestion are in my possession.

On March 2013, reading a note by Wada about the mentioned substance, I immediately stopped the therapy.

I understand now what a serious carelessness I made not informing the team medical staff, with whose members I've been always in contact.

In good faith, I made a huge mistake for which I'm the only person responsible.That's why I want to apologize to Team LAMPRE-MERIDA, its medical staff and its sponsors: I could appreciate the magnitude of the efforts the team is performing in taking care of the image of cycling as a clean sport, so my sadness is even higher for the carelessness I made.”