• ‘There can be no excuse for the leaking of personal and medical data’ • Mo Farah and others had medical information leaked by Russian hackers

The world governing body, the IAAF, has apologised to Mo Farah and other big names whose personal medical information was leaked by the Russian hackers Fancy Bears and admitted the breach of security had put informers at risk.

Sebastian Coe, president of the International Association of Athletics Federations, said he feared that the sustained data attack – between December 2016 and early April this year before being discovered and closed – had damaged the fight against cheats.

“There can be no excuse for the leaking of personal and medical data or the releasing of information on informants and ongoing investigations as this puts those individuals involved at risk and harms the fight against doping” Lord Coe said. “However, we must acknowledge that we need to look at our processes.”

Farah was one of those whose athlete biological passport was revealed to have been investigated in November 2015 in the hack by Fancy Bears. In one file, beside the 34-year-old’s name and under the headline “hematological expert opinion”, is the comment: “Likely doping; Passport suspicious: further data is required.” However, a second database, attached to an email dated April 2016, records “now flagged as normal with the last sample”.

Farah’s representatives have strongly denied any wrongdoing and suggested that “any suggestion of misconduct is entirely false and seriously misleading”.

Farah has yet to comment but he has barred journalists from attending his visit to a school in south-west London to promote Sunday’s Anniversary Games, where he is due to compete in the 3,000m.

The IAAF had significant concerns that some of Kenya’s top athletes were unable to be tested properly, according to the latest Fancy Bears leak. In a letter in March to the head of Athletics Kenya, General Tuwei, the IAAF warned that its testers going to police camps, where many of the Kenyans train, were having “great difficulty accessing athletes and very often have no other choice but to report whereabouts failures against them”.

Mo Farah was suspected, then cleared, of doping by IAAF expert Read more

“We respectfully remind you that, as part of the whereabouts requirements under IAAF Rules, athletes must provide complete and accurate whereabouts where they can be effectively tested,” it added. “This does not seem to be the case for the elite Kenyan athletes working in police forces.

“Whilst this is ultimately an athlete’s individual responsibility, we believe that AK should be able to explain to the police authorities in Kenya the need for elite Kenyan athletes to be easily accessible for testing, at any time.”

Many of Kenya’s greatest runners – including the world 1500m champion Asbel Kiprop, the four-times world 3,000m steeplechase champion, Ezekiel Kemboi, and the Olympic 5,000m champion, Vivian Cheruiyot – are members of the force but their duties rarely extend to more than training in police camps and representing the organisation in Kenya. There is no suggestion of any wrongdoing on the part of the athletes.

Separately, nine Kenyans are on a list released by Fancy Bears who have had abnormal athlete biological passport violations – five are marked as being “likely doping” – although all were allowed to compete following subsequent tests.

Officials estimate the number of positive tests at 50 in the past four years and in April, Jemima Sumgong, the winner of last year’s London and Rio Olympic marathons, was banned for taking banned substances.

The leaks will again fuel suspicions that Kenya is not doing enough to tackle doping. However, the IAAF has demanded far greater testing in recent months and the Guardian understands that all Kenyans who compete at next month’s world championships in London will have undergone a number of pre-competition tests.