The International Olympic Committee announced Friday that 23 athletes had failed doping tests carried out on their samples from the 2012 London Olympics. The announcement was made after 265 samples from the games were retested by IOC using improved techniques as part of its efforts to “protect the clean athletes by keeping dopers away” from this year’s Olympic Games.

Although the athletes’ names were not revealed, the IOC said they were from five different sports and six countries. The athletes who failed the tests will now be banned from competing at the Olympic Games in Rio de Janeiro.

“These reanalyses show, once again, our determination in the fight against doping,” IOC President Thomas Bach said in a statement. “We want to keep the dopers away from the Olympic Games in Rio de Janeiro. This is why we are acting swiftly now. I have already appointed a disciplinary commission, which has the full power to take all the decisions on behalf of the IOC.”

The IOC also said that the analysis is ongoing and that more results may be announced in the coming weeks.

“The athletes, NOCs [National Olympic Committees] and IFs [International Federations] concerned are already being informed, after which the proceedings against the athletes can begin,” the IOC said in the statement.

Friday’s announcement comes just days after the IOC revealed that 31 athletes across six sports had tested positive following re-examination of 454 samples from the 2008 Beijing Games. Later, Russian state media reported that 14 of those athletes were Russian.

Russian track and field athletes are already banned from international competitions and the International Association of Athletics Federations has also set up a task force to decide whether the country’s athletes would be allowed to compete in Brazil.

"There can be no doubt — and no clean athlete in the world should have any doubt — that the IOC would react with its record of proven zero tolerance policy not only with regard to individual athletes, but to all their entourage within its reach," Bach said in a statement earlier this month. "This action could range from life-long Olympic bans for any implicated person, to tough financial sanctions, to acceptance of suspension or exclusion of entire National Federations."