Former President Mwai Kibaki is among VIPs admitted to Nairobi Hospital, the Star has established.
Doctors who spoke in confidence said the ex-President was taken ill on Sunday evening over what was described as "low blood pressure".
“He has been undergoing treatment for the last two days. He is being managed by his doctors,” one of the sources said.
It was not immediately clear the degree of the ailment.
However, reports indicate that he has already undergone several blood tests.
Contacted for comment, Kibaki's private secretary Ngari Gituku allayed fears of the former President's health and dismissed claims he is admitted.
Ngari said Kibaki has been undergoing routine check-ups.
"The retired President has not been admitted to any hospital. But of course the retired President has been going for routine check-ups. The information you have come up with is news to me,” he told the Star on the phone.
Kibaki, 89, has taken a low profile since he retired in 2013 after 10 years at the helm of power.
He was last seen in public in February last year when he turned up at Parliament Buildings where the body of his predecessor Daniel arap Moi lay in state.
Kibaki, who served as Kenya's third President between 2002-2013, has been in and out of hospital and some of the ailments are linked to his old age and the accident he had in December 2002.
Kibaki was in the same hospital in June last year when he underwent treatment after complaining of pain in the lower abdomen.
He had also been admitted to the facility on January 20, 2004, for what doctors said was a blood clot in his right leg. He was also diagnosed with mild high blood pressure at the time.
He was discharged eight days later and was able to walk for the first time since his 2002 road accident at the Machakos junction.
In 2016, the former head of state was flown to South Africa where he successfully underwent surgery on the carotid artery.
In September 2019, Kibaki was in London for a series of medical checks. His knee was also examined.
At the same time, at least three other VIPs have been admitted to The Nairobi Hospital undergoing various treatments, the Star has established.
Apart from ODM leader Raila Odinga, who checked into the hospital on Tuesday, the Star has established that a high-ranking Somalia government official, his wife and two other politicians are admitted.
Sources within the hospital told the Star that the Somalia couple were admitted to the Intensive Care Unit. They are being treated for Covid-19-related complications.
“They have been around for days now. They are in the Covid-19 ICU being managed. We pray for the best,” a doctor, who sought not to be identified for fear of victimisation, said.