Speaking during the official reopening of the Nyayo National Stadium, which had been closed for three years, Kenyatta warned the country's reputation was being damaged by athletes who test positive for banned substances.

He also claimed, however, that the number of Kenyan athletes serving drugs bans is still relatively small, despite Athletics Integrity Unit (AIU) figures showing there are 66 track and field competitors in the nation who are suspended.

"We have had the use of illicit products among our sportsmen," Kenyatta said, according to the Tuko news outlet.

"Even though these cases are tiny, they are troubling."

Marathon runner Patrick Siele became the latest Kenyan athlete to be banned for doping this week after he was found to have evaded a drugs test last December.

Siele ran from drugs testers and then jumped over a fence to get away, according to the AIU.

Notable names on the list of Kenyan runners currently banned include the 2016 Olympic women's marathon champion Jemima Sumgong and former world marathon record holder Wilson Kipsang.

The 2011, 2013 and 2015 world 1500 metres gold medallist Asbel Kiprop is also banned, as is Elijah Manangoi, who succeeded him in 2017.

Earlier this month, the AIU launched a new testing programme aimed at top road runners, including the marathon.

This included stepping up measures to increase the testing of Kenyan athletes.