The entire Chinese orienteering team has been disqualified for cheating at the Military World Games (MWG) in Wuhan, central China, organisers say.
The home team finished first, second and fourth in the women's middle-distance race and second among the men.
But it was soon discovered that they had been illegally aided by spectators and had used markings and small paths prepared for them during Sunday's race.
Their results were annulled after an appeal by other competing teams.
In a statement, the International Orienteering Federation (IOF), whose rules govern MWG competitions, said the competition "was unfortunately overshadowed by extensive cheating by the Chinese team".
The IOF said it had rejected an appeal from the Chinese athletes, and upheld the disqualification ruling.
The MWG are held every year, bringing together army athletes from around the world.
In orienteering, competitors find their way from one point to another using only a map and a compass, with the winner being the person who completes the course in the fastest time.