At least 22 people died as tornadoes ripped through Tennessee early Tuesday, destroying buildings and toppling power lines hours before the southern US state was to vote in Super Tuesday primaries, officials said.

Devastation could be seen across the rubble-strewn state capital Nashville, where a tornado touched down shortly after midnight.

Residents described running for their lives as their homes came down around them, with the authorities reporting that tens of thousands of residents were without power.

"TAKE COVER NOW! THIS IS AN EXTREMELY DANGEROUS STORM!!!" the National Weather Service tweeted as one twister tore through an area west of Nashville. Footage broadcast by the local ABC affiliate showed cars piled up, hangars destroyed and what appeared to be dozens of aircraft smashed into each other at Nashville's John C. Tune airport.

"In the hours ahead, we will continue deploying search and rescue teams, opening shelters across the state, and sending emergency personnel to our communities hit hardest," Governor Bill Lee wrote on Twitter.