A line of fierce storms stretching from Arkansas to Ohio has damaged buildings, flooded roadways and produced dozens of tornadoes in recent days.

Tennessee was hardest hit by extreme weather, with state authorities saying on Saturday that 10 people had died across the western part of the state.

Two people were killed due to floods in Kentucky, according to state Governor Andy Beshear, including a child who was "swept away by floodwaters."

Photos shared on social and local media showed widespread damage from the storm across several states, with homes torn apart, toppled trees, downed power lines and overturned cars.

"Severe, widespread flash flooding is expected" into Sunday in parts of the central-eastern region, the National Weather Service (NWS) said, warning that "lives and property are in great danger."

Two storm-related deaths were recorded in Missouri and one in Indiana, according to local media reports and authorities.

A five-year-old was found dead in a home in Little Rock, Arkansas "in connection to the ongoing severe weather," the state's emergency management agency said in a statement.

"Flooding has reached record levels in many communities," Kentucky's Governor Beshear wrote on social media Saturday, urging residents in the state to "avoid travel, and never drive through water."

More than 100,000 customers were without power in Arkansas and Tennessee as of early Sunday, according to tracking website PowerOutage.us.

The NWS on Saturday said that moderate to severe tornadoes could form in parts of the Tennessee Valley and Lower Mississippi Valley on Sunday, along with "severe thunderstorms."

Scientists say global warming is disrupting climate patterns and the water cycle, making extreme weather more frequent and ferocious.

Last year set a record for high temperatures in the United States, with the country also pummeled by a barrage of tornadoes and destructive hurricanes.