Ireland suffered the first doping blight of the Rio Games on Thursday when 75kg boxer Michael O'Reilly was suspended by his own federation for testing positive for a banned substance. He now faces a ban from competing in Brazil. 

It is understood that middleweight O'Reilly, 23, tested positive for a banned recreational substance, during a random drugs test by Sport Ireland ahead of the Rio Games.

The news came on the eve of an Olympics already overshadowed by the International Olympic Committee’s decision to allow Russian athletes to compete, despite evidence of a state-sponsored doping programme. Russia has eleven boxers at these Games.

The news broke - leaked to an Irish news outlet while the draw for the men's and women's Olympic boxing competition was taking place - with O'Reilly perfunctorily given a bye in the first round. The Irish Amateur Boxing Association (IABA) announced on Thursday evening that they have provisionally suspended the boxer, who had won gold at the European Games this year. 

“The Irish Athletic Boxing Association (IABA) has been notified by Sport Ireland today of an alleged violation of the Irish Anti-doping Rules committed by one of the boxers in our High Performance Unit.

“In following the strict procedures applying to an adverse analytical finding, the athlete in question has been informed and is provisionally suspended. The boxer can request to have a “B” sample tested but cannot participate in any competition or activity prior to the completion of an investigation under Article 8 of the Irish Anti-doping Rules.” 

The Latest: Greece announces 1st positive doping test of Rio

Hours before the opening ceremony, the Greek Olympic committee has announced the first positiv

RIO DE JANEIRO (AP) — The Latest on the Olympics in Rio de Janeiro (all times local):

5:05 p.m.

Hours before the opening ceremony, the Greek Olympic committee has announced the first positive doping test of the Rio Games.

The committee says an unnamed member of the Olympic team failed a doping test in July in Athens. The Greeks say the athlete has left the Olympic Village.

Dozens of athletes have failed doping tests at the last two Olympics, most caught in recent retests of stored samples. The IOC stores doping samples for 10 years so they can be retested when new methods become available, meaning drug cheats who escaped detection at the time can be caught years later.