At least seven people were killed in Arkansas state of southern US early on Friday as dozens of tornadoes swept through several US states overnight.
A 15-year-old girl died in her sleep when a tree fell on her home, police said.
A spokesperson for the state's Emergency Management Department confirmed the deaths of six others in three counties of Arkansas, including three members of one family, and a father and a son.
The severe weather also cut off power supply to thousands of houses in northwest Arkansas but no major structural damage has been reported.
Tornadoes were also reported in Missouri, Texas and Oklahoma although there were no immediate reports of severe damage.
Massive damage to houses and businesses was reported in Kansas city, Missouri, as a violent storm system including hurricane-force winds, hail and heavy rain, moved through the region early Friday morning, injuring at least three people.
"We have reports of houses with no roofs left on them, widespread heavy tree damage with power lines down and roads blocked," Richard King, a public information officer, told the local TV KMBC.
The report said that three people were taken to hospitals with minor injures and emergency staff were still searching for people who might have been trapped in debris.
More than 11,000 families were still in the dark as the electricity technicians were trying to restore the supply.