The death toll from devastating floods in the US state of Kentucky has climbed to 28, including children, with authorities fearing more fatalities as search and rescue operations continue.

Death toll from flash flooding in Kentucky rises to 25 dead and at least a dozen missing.

Images show downtown Mayfield, Kentucky, largely flattened after tornadoes.

US president Joe Biden has declared a major federal disaster in Kentucky after a cluster of powerful tornadoes devastated the state on Friday.

More than 100 people are feared dead after a series of tornadoes ripped through several states in the central and southern US and transformed homes and businesses into piles of rubble late Friday into Saturday.

Kentucky Governor Andy Beshear said on Sunday that widespread damage is making rescue efforts a challenge in his state after tornadoes swept through the region two days ago.

In yet another indication of police brutality against protesters in the United States, an American police officer has been captured on video riding his bicycle over the head of an anti-racism demonstrator in the US city of Seattle, Washington.