BIRMINGHAM, Ala. (AP) — A state corrections official says a reported tornado in northern Alabama hit a state prison but there was no immediate word on damages or injuries.

Corrections spokesman Brian Corbette said Friday a tornado hit the Limestone Correctional Facility, a prison in Limestone County.

Another reported tornado destroyed several houses in northern Alabama as storms threatened more twisters across the region, two days after a storm system killed 13 people in the Midwest and South.

There was no immediate word on any injuries Friday. But the Huntsville-Madison County Emergency Management Office says ambulances are responding to neighborhoods near Huntsville.

Thousands of Alabama schoolchildren are getting out of class early because the threat of tornadoes and other severe weather across the northern half of the state.

More than 20 school systems say they are dismissing classes early Friday because of the possibility of severe storms. Otherwise, the bad weather could hit around the time schools normally dismiss for the day, based on predictions from the National Weather Service.