In a tribute on Saturday, the President said Kyari was in his 20s when he first met him.
He wrote, “Mallam Abba Kyari, who died on April 17, 2020, at the age of 67 from complications caused by the coronavirus, was a true Nigerian patriot. My loyal friend and compatriot for the last 42 years and latterly my Chief-of-Staff he never wavered in his commitment to the betterment of every one of us.”
The President, who condoled with the family of the deceased, described him as one of the best Nigerians.
Buhari said his late aide was an intelligent man who ensured the Presidency functioned efficiently.
He added, “Mallam Abba Kyari was the very best of us. He was made of the stuff that makes Nigeria great. Rest In Peace, my dearest friend.”