Four more cross-country skiers, one of whom could become the first Ethiopian competitor in a Winter Olympics, were suspended for five days after tests showed they had an abnormally high red blood cell count.
Alen Abramovic (Croatia), Pavel Korosteljev, Nikolai Pankratov (both Russia) and Robel Teklemariam (Ethiopia) were shown to have too high haemoglobin values, the International Ski Federation (FIS) said.
Teklemariam, who carried the Ethiopian flag in Friday's opening ceremony, would still be able to race, though, as the 15km classical is scheduled for next Friday, when his suspension would have ended.
But he would miss the 30km pursuit which is scheduled for Sunday, Feb. 12.
However, his red blood cell count will have had to have dropped within acceptable levels under FIS regulations to compete in the classical.
Earlier on Friday, it was announced eight other cross-country skiers had been suspended for five days from Thursday.
The latest four will be suspended from Friday until Tuesday, February 14.
"It should be emphasised that this start prohibition is not a sanction but is considered to serve to protect the health of the athlete," FIS said in a statement.
Among those banned earlier is Germany's Olympic cross-country skiing relay champion Evi Sachenbacher Stehle who broke down in tears when she heard the news.
She was regarded by the ski media as the only serious medal contender of the 12 suspended.
The tests do not indicate the athletes have taken illicit substances but high haemoglobin levels are also a key indication of blood doping, which is why the FIS monitors them.