Authorities in Bahrain say they have opened investigations into the deaths of a policeman and a protester during widespread clashes marking the second anniversary of the anti-government uprising in the Gulf nation.

Officials on Friday said policeman Mohammed Asif was fatally wounded from a "projectile" after attacks from demonstrators. An earlier statement blamed Asif's death late Thursday on a "domestic terror act."

Meanwhile, a separate investigation is under way into the death of a 16-year-old boy, who activists say was killed on Thursday by police birdshot fire.

The unrest has raised questions whether ongoing negotiations between the government and the opposition can ease Bahrain's crisis. The kingdom's majority Shiites are pushing for a greater political voice on the Sunni-ruled island.

Nearly 60 people have died in two years of upheaval.