The 31-year-old long distance runner failed to take an out-of-competition test before the Kigali International Peace Marathon in May 2015. 

It is unclear whether he was given the suspension by the Regional Anti-Doping Organization (RADO) following a series of missed tests.

“I was confused and shocked when I received an email from RADO informing me that I had been banned from any competition organised under IAAF (International Association of Athletics Federations) for the next four years," said Kajuga.

“I agree I did not take those tests, however, I wrote to RADO later apologising and I explained why I did not show up for the test.

"But afterwards, I travelled to Nairobi where I was tested though I was not given the results, that is why I have already appealed the suspension."

Kajuga finished 14th at London 2012 and later that year came 12th in the IAAF World Half Marathon Championships in Kavarna in Bulgaria. 

He was injured for nearly two years after suffering an injury at the 2013 IAAF World Championships in Moscow. 

“I have never used any prohibited substance in my career and I am confused I was not even told I tested positive, so to be banned for four years because of not taking the test, is too harsh." said Kajuga.

Rwanda Athletics Federation secretary general Johnson Rukundo defended Kajuga.

“I think Kajuga may have done it out of ignorance but we have to wait for the final verdict on his appeal," he said.

"In the meantime, we are going to start a campaign to educate our athletes that on and off competition doping tests are done and failure to take them is punishable."