Nairobi — Kenya's Shadrack Chesir has been disqualified from the Poznan Half Marathon after in-competing anti-doping tests revealed that he had tested positive for a prohibited substance.

In a statement released on their website, the organising committee said the results of the athlete's Sample A test turned positive, which Chesir did not contest by requesting for a Sample B test.

"The competitor resigned from the right to Sample B. The result of the Sample A were considered valid and the organizer, Poznan Sports and Recreation Centre, disqualified the competitor. He was also banned in competing in runs organized by POSiR - Poznan Marathon and Poznan Half Marathon - for a period of two years," the statement read.

Chesir had finished fourth in the road race held last month, clocking 1:01:20 in a race won by Ethiopian Haftamu Gebresilase in 1:00:27.

Two other Ethiopians, Solomon Berihu and Sikiyas Misganaw, finished second and third after timing 1:01:06 and 1:01:11 respectively.

Chesir's disqualification comes less than a week after the provisional suspension of the world record holder for the men's 10km, Rhonex Kipruto, after his athlete biological passport (ABP) showed traces of use of a prohibited substance.

His suspension came a day after another Kenyan, the 2014 World Junior 10,000m bronze medalist Nicholas Kosimbei, was provisionally suspended for testing positive for Trimetazidine.