Washington  - A gun is believed to have killed at lease nine people in a shooting spree in southern Alabama before taking his own life, the Alabama Department of Public Safety said late Tuesday.

The spree through a mostly rural area near the Florida state line including shootings in at least four locations, the state police statement said.

The gunman, who was described as carrying a semiautomatic weapon, is believed to have acted alone.

"This is a very complicated investigation that is unfolding, with multiple crime scenes and a number of agencies working together," the state police statement said.

The first gunfire was reported late Tuesday afternoon in the town of Samson, where a total of six adults and a child were found shot to death inside three houses.

After leaving the town, the gunman is believed to have opened fire on an Alabama state trooper on a highway. The trooper suffered minor injuries from broken glass, and his squad car was struck by seven bullets.

Two more victims were shot to death along the same highway, one at a business and the second at a petrol filling station.

Outside the nearby town of Geneva, the gunman is suspected of unleashing 30 rounds at a metal manufacturing company with police in pursuit. The Geneva police chief was wounded at the scene.

The suspect entered the small factory, and police followed after hearing more gunfire to find the body of the gunman with an apparent self-inflicted bullet wound.

Authorities were investigating a possible related arson at a house in another part of southern Alabama, where the body of a potential 10th victim was found.

Several additional people were wounded in the shooting spree.