Athletics Kenya has suspended Josephine Jepkoech Jepkorir and Agatha Jeruto Kimaswai for two and four years respectively after they tested positive for the banned anabolic agent norandrosterone.
The bans come less than six weeks after 400 metre runner Joyce Zakary and 400m hurdler Francisca Koki Manunga were thrown out of the International Association of Athletics Federations (IAAF) World Championships in Beijing for similar offences.
Road runner Jepkorir has been sanctioned for failing a doping test conducted on December 31, 2014 during the Corrida de Sao Silvestre in Luanda, Angola.
Her results from both that race, and February’s Ras al Khaimah international half marathon have been annulled and she is said to be forfeiting prize and appearance money.
"Owing to the period when the infraction was registered a two-year sanction has been imposed on the athlete effective from March 15, 2015 and will end on March 14, 2017," read an Athletics Kenya statement.
Kimaswai, an 800m athlete, has been sanctioned for failing a doping test during an out of competition mission on April 14, 2015 in Eldoret, Kenya.
"In reference to IAAF Rule 40.2 (a) ii a four (4) year period of ineligibility has been imposed on the athlete effective May 20, 2015 and will end on May 19, 2019," added the statement.
Jeruto was on the books of the Rosa Associati stable, which expelled fellow Kenyan Rita Jeptoo from its management after the marathon runner received a two-year ban in January for erythropoietin (EPO) violations.
Meanwhile, the International Athletics Consultancy (IAC), which was led by the late respected manager Zane Branson, has denied reports linking Jepkoech to their stable.
"IAC states that Jospehine Jepkoech Korir was not managed by the late Zane Branson/IAC and in the strongest possible terms we object incorrect and irresponsible reporting," said IAC special projects manager, Davor Savija.
The two latest failed tests will focus more unwelcome attention on the Kenyan anti-doping operation, which has been the subject of many of the allegations made in the recent documentaries made by German TV company ARD which is operating in conjunction with The Sunday Times.
August 2015: Two female Kenyans suspended in Beijing after positive doping tests
April 2015: Leading Kenyan athletes protest at "unprofessional" agent suspensions
April 2015: Athletics Kenya suspends Italian and Dutch agencies pending investigations into doping cases
March 2015: Every African country should have own anti-doping agency, claims Diack
February 2015: IAAF's Kenya laboratory ready soon as new World Marathon Majors deal to boost anti-doping efforts launched