“Sad that I haven’t travelled to Oregon yet and 100m is in 2 days. Visa delays!!” the 26-year-old Kenyan sprinter posted on Instagram.
Omanyala, who set the African 100m record of 9:77 in September last year, is due to race in the heats on Friday at the world championships in Eugene, Oregon.
He is currently the third quickest man in the world this season behind Americans Fred Kerley and Trayvon Bromell.
“We are anxiously waiting for the US embassy to issue visas for a number of athletes, including Omanyala. Hopefully they will be able to fly out today,” Athletics Kenya executive member Barnabas Korir told AFP.
It was not clear how many athletes were affected.
Omanyala is also due to compete at the Commonwealth Games in the English city of Birmingham that begin on July 28 and run till August 8.
