Inside the Games
Twenty-three athletes have tested positive for banned substances following reanalysis of samples from the London 2012 Olympics, it has been confirmed.
The athletes come from six different countries with the failures spanning five sports.
In all, 265 doping samples from London were re-tested, using the latest technology available.
An intelligence gathering operation began in August 2015 with the International Olympic Committee (IOC) targeting those athletes who are likely to compete at the Rio 2016 Games this year.
The 23 athletes have all failed their A samples but none have yet been officially named.
All face being banned from Rio and those who made the podium in London could lose their medals.
This comes after the IOC announced on May 17 that 31 athletes had failed following reanalysis of Beijing 2008 samples.
The IOC has now confirmed that one more sample from the Chinese capital has failed.
Some athletes may have had samples tested from both Games.