At least two people have been killed and more than a dozen injured in Oklahoma after mulitple twisters swept through the US state reducing homes to rubble.
Oklahoma state medical examiner's office spokeswoman Amy Elliot identified the two people killed during Sunday's storms as 79-year-old Glen Irish and 76-year-old Billy Hutchinson.
More than two dozen tornadoes were spotted in parts of Iowa, Oklahoma, Kansas and Illinois, according to the National Oceanic and Atmospheric Administration and local news reports.
They formed part of a massive, northeastward-moving storm system that stretched from Texas to Minnesota, producing 80mph winds and huge hail stones.
Forecasters say more tornadoes could hit on Monday in roughly the same area hit on Sunday night.
Thousands of homes and businesses were without power in Wichita in Kansas after a power cut.
At least four separate tornadoes touched down in Oklahoma, including one in the town of Shawnee which smashed through a group of mobile homes.
A storm spotter told the National Weather Service that the tornado left the earth "scoured" at the mobile home park.
Some 16 counties of the state were declared disaster areas by Oklahoma Governor Mary Fallin.
Forecasters had been warning for days that a powerful front was expected to blast through the region, spawning potentially destructive twisters.
Authorities had put counties in Kansas, Nebraska, Iowa, Oklahoma, Minnesota, Wisconsin, Illinois and Missouri on alert.
The storm system was described by the US National Weather Service as "violent" and "extremely dangerous".
On Thursday, 10 tornadoes tore through Texas killing at least six people and injuring dozens as they flattened homes and downed power lines.