The Court of Arbitration for Sport (CAS) has upheld a ban on Russia's track and field athletes competing at this summer's Olympic Games in Rio de Janeiro.

Athletics' world governing body the IAAF issued the ban last November following allegations of widespread doping and coverups by a number of Russian athletes at the 2012 Olympics in London.

CAS heard Russia's appeal, which sought to allow participation for athletes who had not been accused of doping, earlier this week but said today that it had 'unanimously' decided to back the IAAF ruling.

In a statement, the IAAF said: "Today's judgment has created a level playing field for athletes. The CAS award upholds the rights of the IAAF to use its rules for the protection of the sport, to protect clean athletes and support the credibility and integrity of competition."

IAAF president Sebastian Coe added: "While we are thankful that our rules and our power to uphold our rules and the anti-doping code have been supported, this is not a day for triumphant statements.

"I didn't come into this sport to stop athletes from competing. It is our federation's instinctive desire to include, not exclude.

"Beyond Rio the IAAF taskforce will continue to work with Russia to establish a clean safe environment for its athletes so that its federation and team can return to international recognition and competition."

Olympic governing body the IOC revealed on Wednesday that it is considering whether to impose a blanket ban on all Russian athletes competing in Rio.