World number one Novak Djokovic has failed in his bid to play at next week's Miami Open after being denied entry to the United States.
The 22-time Grand Slam winner, 35, had applied for special permission to enter the US because he is not vaccinated against Covid-19.
The US requires international visitors to be vaccinated and proof will be required until at least 10 April.
Djokovic withdrew from the ongoing Indian Wells event for the same reason.
"Obviously, we're one of the premier tournaments in the world, we'd like to have the best players that can play," said Miami Open tournament director James Blake.