Hurricane Melissa has lost its tropical structure and transitioned into a powerful post-tropical cyclone over the north-west Atlantic, the US National Hurricane Center (NHC) has confirmed.

The storm, which battered parts of the Caribbean and Bermuda with fierce winds and heavy seas, has now moved away from land. All storm watches and warnings have been lifted.

Bermuda experienced storm-force winds and gusts near hurricane strength overnight before conditions improved early Friday.

Forecasters say the system will continue to move northeastward over open waters and gradually weaken, though rough seas and large swells are expected to linger for some time.