By Amy Tennery

(Reuters) RIO DE JANEIRO - Long-distance running great Haile Gebrselassie condemned a recent spate of doping incidents in sport, after a Kenyan track coach was caught trying to take a drug test for one of his athletes.

Sprint coach John Anzrah was sent home last Thursday after wearing the accreditation of 800 meters runner Ferguson Rotich and giving a urine sample in a doping test. He now faces possible criminal charges back home.

Two-time Olympic gold medalist Gebrselassie of Ethiopia lamented the failure of authorities to crack down.

"I don't understand," Gebrselassie told Reuters, pointing to "a lack of seriousness" surrounding the issue of banned substances.

Gebrselassie also acknowledged that the sophistication of doping programs has made it increasingly difficult to uncover abusers within the sport.

“The doping issue, it [has] become more complicated -- the tactic[s], the way they cover it up,” Gebrselassie said.

(Reporting By Amy Tennery in Rio de Janeiro)