Under the American travel requirements, any non-US citizen flying into the country must be fully vaccinated against coronavirus to be allowed to enter.

The US Transportation Security Administration has confirmed that the ruling will remain in place until April 10, meaning Djokovic will be unable to play in two Association of Tennis Professionals (ATP) Masters 1000 events if he has not received two shots of a COVID-19 vaccine.

The Indian Wells Masters is scheduled to run from March 6 to 19 before the Miami Open is set to be held from March 20 to April 2.

Djokovic is a six-time Miami Open champion and has won the Indian Wells Masters title on five occasions.

"Look, if it is official, then it is," said Djokovic when asked for his reaction to the extension of the vaccination rules.

"I mean, what can I do?

"Nothing, that's it.

"You know my position.

"It is what it is.

"I'm hoping [to participate], but if I can't go, I can't go."

Djokovic was not able to play in the US Open or any other high-profile ATP Tour events in the country last year due to the American immigration rules.

The 21-time Grand Slam champion was also deported from Australia before the 2022 Australian Open when the country's Government cancelled his visa on grounds of public interest.

The decision left Djokovic facing a three-year ban from entering Australia but this has now been revoked, allowing the 35-year-old to return.

Australia no longer requires new arrivals to submit proof of their vaccination status, so Djokovic has been granted a temporary visa to enter Australia.