BIRMINGHAM, Ala. -- Firefighters are starting to go house-to-house in an effort to rescue people trapped in their homes after storms did major damage to buildings, an emergency management official said.

Fire crews are starting the search in Center Point, where there are reports of an unknown number of people trapped, said Bob Ammons, duty manager of the Jefferson County Emergency Management Agency.

Rescuers will do "whatever it takes" to get to the residents, Ammons told The Associated Press before dawn this morning.

There were no immediate reports of injuries.

Ammons says his agency has reports of damage in the Jefferson County towns of Center Point, Clay, Trussville and in the unincorporated community of Adger.

Tornado warnings were issued in parts of central and northern Alabama in the early morning hours today as powerful storms rolled across the state. There were several reports of severe damage to homes.

Hard-hit areas included the Maplesville area, according to reports from the National Weather Service. The weather service was also reporting damage to buildings in the St. Clair County town of Springville.

There were also reports of major damage to homes in the Oak Grove area of Jefferson County, WBMA-TV reported.

Several storm shelters had opened in the northern Alabama counties of Colbert, Lauderdale, Madison and Marshall, WAFF-TV reported.

The weather service had earlier issued a tornado watch for 30 Alabama counties until 10 a.m. Monday.

The Alabama storms were part of a system threatening parts of the South and Midwest overnight.