A tornado in the midwestern U.S. state of Indiana has killed at least 22 people and injured over 200 others.

Witnesses say the tornado formed along a line of thunderstorms and touched down in Henderson, Kentucky, early Sunday morning. It then skipped across the state border to rip through several Indiana communities.

Twelve of the victims were killed at a mobile home park in the city of Evansville, Indiana.

Although warnings were issued before the twister, many people were asleep and did not hear them.

Officials say the tornado left a path of damage more than 30 kilometers long and more than one kilometer wide. It reduced houses to rubble, scattering debris across the countryside, and stripping foliage off of trees.