The International Olympic Committee has announced that all athletes from Russia and Kenya must individually prove their innocence before being allowed to compete at the Rio Olympics this summer.
The World Anti-Doping Agency (WADA) has declared both countries "non-compliant" with its rules, leading the IOC to take an unprecedented step in order to prevent another doping scandal rocking the Games.
The decision was unanimously agreed at an emergency summit in Lausanne and applies to all competitors, with the sport's international federations themselves carrying out additional tests.
"The conclusion of the summit was that this non-compliance declaration, and the substantial allegations related to it, put very serious doubts on the presumption of innocence for athletes coming from these two countries," IOC president Thomas Bach said in a statement.
"Therefore, each athlete coming from these two countries will have to be declared eligible by their respective international federation following an individual procedure and evaluation of the situation.
"And in this individual evaluation, tests from laboratories that are tainted or non-compliant, cannot be taken into consideration. The respective [international federation] will have to take into account other reliable tests, that means international tests, or tests supervised by international authorities."
This summer's Olympics will begin on August 5 and end on August 21.
