With nine weeks left before the Summer Olympics start in Rio de Janeiro, Brazil, the International Olympic Committee is working to keep past cheaters out of the Games to show it's getting tougher in the fight against drugs that give an unfair edge. Officials say 31 athletes in six sports from 12 countries could be barred after re-tests of their blood samples from the 2008 Summer Olympics found evidence of doping. Samples from the last Summer Games four years ago in London also are being rechecked.

At the same time, global athletic officials are considering whether to bar Russian track athletes – or even every Russian team – from Rio after disclosures of a widespread, government-backed doping program. Russian runners, hurdlers, long jumpers and other track athletes currently are suspended from global events – a status that could be lifted June 17 by the governing body of track and field.

In addition, dozens of Russian competitors at the 2014 Winter Olympics in Sochi, Russia – including at least 15 medal winners – used prohibited substances to gain strength and endurance, according to a former head of the country’s anti-doping lab. In an effort to avoid a sweeping ban on Olympic participation this August, the sports minister in Moscow says officials, coaches and athletes made "serious mistakes . . . and neglected the principle of fair play," though he doesn't admit any state role. "Russia is committed to upholding the highest standards in sport and is opposed to anything that threatens the Olympic values," Vitaly Mutko wrote recently in The Sunday Times, a British newspaper. But he added: "It cannot be right that clean athletes should suffer for the behavior of others. . . . These are men and women who have sacrificed years of their lives striving to compete at the very highest level, who have dreamed of taking part in the Olympic Games, and who now face having their sacrifice wasted. . . . We will do everything humanly possible to ensure our athletes are a part of clean, fair and enthralling Games."

Russian official says: "Doping is a global problem, not just a Russian one." -- Vitaly Mutko, sports minister

Olympic official says: "We do not allow cheats to win. . . . Dopers have no place to hide." -- Thomas Bach, International Olympic Committee president

Columnist says: "Hundreds of athletes who relied solely on their blood, sweat and tears have had medals and records stolen by those powered by pharmaceuticals with unpronounceable names." – Nancy Armour, USA Today