Czech Republic - Swedish cross-country skier Britta Norgren has been suspended from the opening 10-kilometres cross-country race at the Nordic world championships on Thursday due to an elevated amount of red blood cells.

The mandatory pre-competition blood screening revealed slightly elevated levels, the Swedish ski federation said in a statement on Wednesday.

Athletes with elevated blood levels are suspended for five days for health reasons and can then compete again if another screening goes well. The higher levels can be an indication of doping.

In the case of Norgren, Swedish officials cited a combination of high-altitude training training and a stomach bug as an explanation for the elevated levels. Norgren is not rated a medal contender in Liberec.

The ruling body FIS is conducting more than 1,000 doping tests around the Liberec championships which run from Thursday until March 1. (dpa)