SALVO, North Carolina - The US and International Olympic Committees asked sport's highest court on Wednesday to make a definitive ruling on an eligibility rule that could keep some athletes out of the London Olympic Games.

The Court of Arbitration for Sport (CAS) has been asked to determine the validity of IOC Rule 45, which bars any athlete receiving a doping sanction of greater than six months from competing at the next Olympic Games.

Dozens of athletes, including US Olympic 400 metres champion LaShawn Merritt, could have their eligibility for the 2012 London Olympics affected by the CAS decision.

The rule, adopted in 2008, has been criticized as creating a second penalty for athletes who have served their doping suspension.

The IOC has maintained the rule is not a sanction but an issue of eligibility and that it has the right to put conditions on participation in the Olympics.

"In the interest of ensuring that all eligible athletes are able to compete in their respective Olympic qualification process, and to establish a degree of certainty as we head toward the Olympic Games in London, the USOC and the IOC have agreed to place the question of the regulation before the CAS," USOC chief executive Scott Blackmun said in a statement.

IOC Director General Christophe De Kepper said a ruling by CAS would erase any confusion ahead of next year's Olympics.

"This arbitration will provide certainty in the lead up to the 2012 London Olympic Games," he said.