The men's marathon world record holder, Kenya's Kelvin Kiptum, 24, has died in a road accident in his home country.
He was killed alongside his coach, Rwanda's Gervais Hakizimana, in a car on a road in western Kenya on Sunday.
Kiptum made a breakthrough in 2023 as a rival to compatriot Eliud Kipchoge - one of the greatest marathon runners.
And it was in Chicago last October that Kiptum bettered Kipchoge's achievement, clocking the 26.2 miles (42km) in two hours and 35 seconds.
The two athletes had been named in Kenya's provisional marathon team for the Paris Olympics later this year.
Paying tribute to Kiptum, Kenyan Sports Minister Ababu Namwamba wrote on X: "Devastatingly sickening!! Kenya has lost a special gem. Lost for words."
Kenya's opposition leader and former prime minister, Raila Odinga, said the country had lost "a true hero" and was mourning "a remarkable individual... and Kenyan athletics icon".