British police say a taxi driver has killed 12 people and wounded 25 others in Britain's worst shooting spree in more than ten years.

Authorities say Derrick Bird on Wednesday apparently killed himself after shooting people in 30 separate locations, in Britain's typically quiet northwestern county of Cumbria.

At Least 12 Dead in British Shooting Rampage

British media say the 52-year-old Bird started a three-hour-long rampage by killing his twin brother. Bird also allegedly killed a fellow cab driver, a farmer's son, and a bicyclist, among other victims.

At Least 12 Dead in British Shooting Rampage

British police found Bird's body in the woods near the village of Boot.

At Least 12 Dead in British Shooting Rampage

They are searching for a motive for the shootings. British police say they do not know if the victims were targeted or gunned down at random.

Britain's Queen Elizabeth says she shares in the grief and horror of the whole country. Prime Minister David Cameron says he is alarmed and shocked.

Gun violence is rare in Britain, where gun laws are strict.