Four US troops die in Afghan blast

Four American troops have been killed in a roadside bomb explosion in eastern Afghanistan, Nato said today.

The deaths come amid a particularly bloody period for US forces in the country, with 18 service members killed since Saturday to bring this month's total to 53.

Another member of the international coalition, whose nationality has not been released, was killed yesterday.

July was the deadliest month for US troops in Afghanistan since the 2001 invasion, with 66 killed.

Southern and eastern Afghanistan have seen the heaviest fighting. Those areas are also closest to the border with Pakistan, where the insurgents maintain training bases for recruits to be later infiltrated into Afghanistan.