Bahraini police clashed with anti-government protesters in street battles today that left at least one teenager dead.
The demonstrators were marking the second anniversary of the uprising in the country and included groups chanting against talks with the ruling monarchy.
Bahrain's Shi'ite majority wants a greater political voice in the Sunni-ruled kingdom.
More than 55 people have been killed in the two-year unrest, which began with massive marches in February 2011.
The 16-year-old who died today was killed by police birdshot in the mainly Shi'ite village of Dih, west of Manama.
Street battles broke out before dawn in some Shi'ite neighbourhoods and opposition groups called a nationwide strike to mark the anniversary.
The main Shi'ite factions opened talks with government officials and Sunni envoys last week, but some groups oppose dialogue, fearing it will be fruitless.
Foreign Minister Alistair Burt's admission that the Cameron government has "supported" a survey of attitudes to US drone strikes in Pakistan's tribal areas amounts to a tacit admission of British involvement.