A large segment of a free-falling Chinese rocket re-entered the Earth's atmosphere and disintegrated over the Indian Ocean near the Maldives on Sunday, amid deep concern worldwide that the uncontrolled 18-tonne object may crash into an inhabited area.

"After monitoring and analysis, at 10:24 (0224 GMT) on May 9, 2021, the last-stage wreckage of the Long March 5B Yao-2 launch vehicle has re-entered the atmosphere," the China Manned Space Engineering Office said in a statement, providing coordinates for a point in the Indian Ocean near the Maldives.

It added that most of the segment disintegrated and was destroyed during re-entry.

Monitoring service Space-Track, which uses US military data, also confirmed the re-entry.

"Everyone else following the #LongMarch5B re-entry can relax. The rocket is down," it tweeted.

"We believe the rocket went down in the Indian Ocean, but are waiting on official data from @18SPCS," it added in a separate tweet, referring to a squadron of the US Space Force.

The Long March-5B rocket was used to launch the first module of China's new space station into Earth orbit on April 29.

The segment's descent matched predictions by some experts that any debris would have crashed into the ocean as 70 per cent of the planet is covered by water.  But the uncontrolled re-entry of such a large object had sparked concerns about possible damage and casualties.

American and European space authorities were among those tracking its orbits and trying to determine where it may come down.

Defense Secretary Lloyd Austin had said the US military had no plans to shoot it down, but suggested that China had been negligent in letting it fall out of orbit.

Last year, debris from another Long March rocket fell on villages in the Ivory Coast, causing structural damage but no injuries or deaths.

To avoid such scenarios, some experts have recommended a redesign of the Long March-5B rocket — which does not have the ability to control its descent from orbit.