More than a dozen people were injured, some critically, roofs were torn off, homes wrecked, vehicles overturned and roads blocked by toppled trees on Saturday.

Thousands across Mississippi were without electricity, and downed power lines and trees blocked roads.

Tornadoes were also reported in Louisiana, Arkansas and Alabama, and the severe weather continued to track eastward.

The weather hampered crews trying to clean up an oil spill after an explosion on an offshore oil rig caused the platform to sink this week off the coast of Louisiana.

The storms also damaged a tank at a chemical plant in Tallulah, causing a small nitrogen leak.