(Adds details and background)

LONDON, March 31 (Reuters) - Two British NATO soldiers were killed in an explosion in southern Afghanistan on Sunday, Britain's Defence Ministry said on Monday.

Britain has about 7,800 troops in Afghanistan, mostly in Helmand, a largely desert province cut in two by a strip of lush fertile land which produces nearly half the world's opium.

"The soldiers were conducting a patrol in the vicinity of Kajaki, Helmand Province, when the vehicle they were travelling in was caught in an explosion," the ministry said in a statement.

The deaths brought to 91 the number of British troops killed in Afghanistan since the Taliban were ousted from power in late 2001 by U.S.-led forces.

Britain is a major troop contributor to the NATO force in Afghanistan fighting Taliban and al Qaeda insurgents. (Reporting by Kate Kelland, Editing by Tim Castle)

AlertNet news is provided by