The death toll rose to 12 from tornadoes that ripped through southern US states over the weekend, officials said Monday.

Rescue workers were still seeking victims and survivors in Mississippi and Alabama, where dozens of homes were damaged or destroyed.

In Mississippi, the death toll remained at 10 with several others injured, according to emergency management officials.

Alabama authorities cited two fatalities including one person who was hit by a felled tree in Etowa County, said local emergency spokesman Michael Amberson, who added that another victim died in nearby Walker County.

"This is a huge tornado, very, very powerful and intense," Mississippi Governor Haley Barbour told Fox News television. "It's a very bad storm, lots of people hurt; but by God's grace, ten killed, if you saw the destruction, you'd say gee, what a blessing it was only ten."

Saturday's storms tore roofs off buildings, reduced homes to splinters, overturned vehicles, downed power lines and toppled trees onto the roads.

Florida Power & Light said meanwhile an estimated 10,000 customers were without electricity in the state, which was also affected by the storms.

The Mississippi Emergency Management Agency counted nearly 200 homes damaged by the storm, and Barbour said at least 21 locals who sustained injuries had been ferried to nearby hospitals in helicopters or ambulances.

Survivors told dramatic stories of narrow escapes from tornadoes that were up to a mile (1.6 kilometers) wide and packed winds of nearly 165 miles per hour (265 km/h), according to meteorologists.