A storm spawning multiple tornadoes struck Sunday in south-western Missouri, causing major damage and numerous fatalities, according to local newspapers, dpa reported.
A local emergency management official said that there were 24 deaths in Joplin, Missouri, the News-Leader newspaper in nearby Springfield reported online.
Missouri Governor Jay Nixon declared a state of emergency, called out the National Guard to support local emergency services and mobilized other state agencies to assist.
"These storms have caused extensive damage across Missouri, and they continue to pose significant risk to lives and property," Nixon said.
The storm struck with multiple funnel clouds in the south part of Joplin about 5:45 pm (2245 GMT), according to the National Weather Service.
The governor's office said that Joplin's St John's Regional Medical Centre was stuck.
Electricity and telephone communications were largely knocked out by the storm.
Authorities were setting up a shelter at Missouri Southern University in Joplin for people who had lost their homes.