Elon Musk's SpaceX called off the latest test flight of its Starship rocket just before its scheduled launch on Monday, citing an unspecified problem with the behemoth spacecraft.

"Standing down from today's flight test attempt," SpaceX posted on X, also owned by Musk. "Starship team is determining the next best available opportunity to fly."

The world's biggest and most powerful rocket was set to take off with no crew at 6:45 pm (2345GMT) from SpaceX's Starbase facility in Boca Chica, Texas.

A rescheduled launch has yet to be announced, though SpaceX employee Dan Huot said it was expected "to be about 24 hours" during a live feed of the event.

The flight will be Starship's eighth orbital mission overall and first since a dramatic mid-air explosion over the Caribbean during its last trial.

Standing 403 feet (123 meters) tall -- about 100 feet taller than the Statue of Liberty -- Starship is designed to eventually be fully reusable and plays a crucial role in Musk and SpaceX's vision of colonizing Mars.

Meanwhile, NASA is awaiting a modified version of the rocket for its Artemis program, which aims to return astronauts to the Moon.

The US Federal Aviation Administration (FAA) grounded Starship after its previous flight on January 16 ended with the upper stage disintegrating in a fiery cascade over the Turks and Caicos Islands, prompting cleanup efforts for fallen debris.

On Friday, the FAA said Starship could return to flight before it finalizes its review of SpaceX's "mishap investigation."

During Joe Biden's presidency, Musk frequently accused the FAA of excessive scrutiny over SpaceX's safety and environmental concerns.

Now, as one of President Donald Trump's closest advisors, the world's richest person faces allegations of wielding undue influence over regulatory agencies overseeing his companies.

For the upcoming flight, SpaceX says it has introduced numerous upgrades to the upper-stage spacecraft, enhancing its reliability and performance.

The mission, expected to last just over an hour, includes another attempt to catch the booster stage using the launch tower's "chopstick" arms -- a feat SpaceX has successfully executed twice, including in the last flight.

Additionally, the company will deploy Starlink simulators designed to mimic next-generation Starlink satellites, which will burn up upon atmospheric re-entry.

Eventually, SpaceX aims to recover the upper stage as well, but for now, it is targeting an ocean splashdown off the west coast of Australia, as in previous flights.