Tornados tore through parts of the US states of Arkansas, Missouri and Illinois on Friday, killing at least six people and leaving damage and power outages in its wake, authorities said.

"Three fatalities have been reported in Washington County," the Arkansas state emergency management office said in a statement. The fatalities were near the town of Cincinnati, Arkansas, it added.

The storm struck Arkansas around 6:00 am local time, cutting a swath through four counties and leaving at least eight injured, police said.

In Missouri, a tornado struck a cluster of trailers in rural Dent County, killing two women, one 64 years old and the other a 21-year-old, said county sheriff Rick Stallings.

"It was total devastation of the trailers and the pole barn," said Stallings, referring to an open-sided barn. "It was unidentifiable."

There were no other casualties, and other houses on the property suffered only slight damage, he said.

Another person was killed by a tornado that touched down near the town of Rolla, about 100 miles (160 kilometers) southwest of St. Louis, in Phelps County, Missouri.

"There was a fatality related to the tornado in Phelps county," said Stacy Smith, a dispatcher for the Phelps County sheriff's office. "There were some injured but I have no information as to numbers or severity."

Governor Jay Nixon declared a state of emergency in Missouri, saying his administration was "ready to provide whatever resources are necessary to help with rescue, recovery and public safety operations in the wake of these deadly storms."

The same system also passed through Illinois near Belleville, CNN television reported, citing reports of five additional serious injuries.

Mayor William Nolan of Sunset Hills, Missouri, a town located close to St Louis, said that despite the destruction in his town, which included torn off roofs, there were no injuries.

"It's incredible, absolutely incredible," Nolan told CNN. "Cars overturned, trucks overturned... it's hard to believe that such a thing could happen to our city."