The World Anti-Doping Agency banned the inhalation of xenon and argon gas Sunday, saying it could illegally enhance the performance of athletes.

Top Russian athletes were said to have used xenon at Olympic Games from Athens 2004 right up to the Sochi 2014 Winter Games.

Inhaling the gas encourages the production in the body of the hormone Erythropoietin (EPO), which encourages the formation of red blood cells in the body to improve performance.

In addition to banning the use of xenon and argon, WADA decided to place the substances on its prohibited list.

"The message to any athlete is loaded and clear, it's going onto the ban list," WADA president Craig Reedie told AFP after the agency's two-day executive committee and foundation board meetings.

"So if in doubt, do not."

WADA's executive committee unanimously approved the ban, which will go into effect after a 90-day delay for national anti-doping organizations to implement the change.

Russia's athletes enjoyed a hugely successful Winter Games in Sochi, winning 13 gold medals and topping the final medals table.

The country until recent years had a dire reputation for the doping of athletes dating back to the Soviet system.

However Russia has now taken steps to clean up its act including the creation of its own anti-doping agency RUSADA.

The research institute of the Russian defense ministry reportedly set out guidelines in 2010 for the administration of xenon gas to athletes.