A US gunman went house to house, fatally shooting seven people and wounding one in a small southern Missouri town before apparently committing suicide in a vehicle, authorities said.

Violent storms tore through four Midwestern states, killing three people in northern Missouri, damaging dozens of homes and leaving thousands without power.

US President George Bush will tomorrow visit areas hit by a tornadoes that have killed at least 20 people in several American states, including eight students at an Alabama high school.

Tornadoes swept through portions of the Midwestern United States, killing at least three people in Missouri and blowing roofs off homes in Illinois and Arkansas.