Updated

Bahrain's public prosecutor's office says shotgun pellets caused the death of a 16-year-old youth last week in an incident that has sharply raised tensions in the Gulf kingdom.

Shiite-led protest groups accuse security forces of abuses in the death of the Husam al-Hadad. The island nation's Western-backed Sunni monarchy has promised an investigation.

More than 50 people have died in Bahrain's unrest since clashes began in February 2011 between government forces and majority Shiites seeking a greater voice in the nation's affairs.

Monday's statement by public prosecutor spokesman Nawaf Hamza says the boy died of injuries from shotgun fire. It said a probe is in progress.

Bird shot is often used by Bahrain's security forces.