Violent tornadoes ripped through parts of the United States, wiping out schools and toppling semitractor-trailers in several states, part of a monster storm that has killed at least 32 people as more severe weather was expected late on Saturday.

A dangerous tornado outbreak which started on Friday evening continued into the first half of the weekend with nearly 2 dozen deaths across the nation's heartland and South.

Tornadoes in the South and Midwest overnight and early Saturday left 11 dead in Missouri. More tornadoes are forecast Saturday and Sunday.