Novak Djokovic has been ruled out of the Miami Open after tournament organisers "exhausted all the options" in an effort to secure him a travel exemption.

The 22-time grand slam winner withdrew from the Indian Wells Open as he is unable to play in the United States.

He is not vaccinated against COVID-19, which remains a requirement of international travellers, but Djokovic had hoped to be granted special permission to enter the country.

US tennis authorities and a number of politicians also expressed support for an exception being made for the 35-year-old Djokovic, with US president Joe Biden urged to reconsider policy.

Even last week, Serbian superstar Djokovic was clinging to hopes of playing the Miami Open, which he has won six times.

However, tournament director James Blake told Tennis Channel there is no chance of that happening, despite extensive efforts.

"Obviously, we're one of the premier tournaments in the world, we'd like to have the best players that can play," said Blake, a former world number four.

"We did all that we could. We tried to talk to the government, but that's out of our hands. We tried and he wasn't able to play."

Blake said he was in the same position as Indian Wells tournament director Tommy Haas, being unable to influence government-level decisions.

"We tried to get Novak Djokovic to be allowed to get an exemption, but that wasn't able to happen," Blake said. "We'd love to have him, and he’s our greatest champion, won it six times here.

"Unfortunately, that's way above my pay grade."

Blake added: "We exhausted all the options we knew of. Hopefully Novak will be back this year and hopefully he will be back for all the later events in the States including Cincinnati and the US Open."