Moscow - Russian biathlon star Albina Akhatova on Tuesday claimed she was innocent of doping and vowed to work with officials to clear the matter.

The four-time world champion was one of three Russian biathletes who tested positive for an unnamed substance, believed to be a new generation of the blood booster EPO.

Akhatova, as well as Ekaterina Iourieva and Dmitri Yaroshenko were identified shortly before the start of the world championships in Pyeongchang by the world controlling body IBU as having returned a positive test at the World Cup season-opener in Ostersund, Sweden, in early December.