KABUL, Afghanistan - Every day across Afghanistan, rural people crowd aboard rickety communal taxis that ply the roads linking remote towns and villages. And every day, they run the risk of what happened Thursday morning in Helmand province.

A roadside bomb ripped through a minibus in the Nahr-e-Saraj district in central Helmand, incinerating the vehicle and killing 14 people - men, women, and children.

The Taliban and other insurgent groups routinely seed roads that run through battle zones with IEDs, or improvised explosive devices, in hopes of killing and maiming Western troops - which they do, in large numbers. But more often the victims are Afghan civilians.

This has been the war's deadliest year for noncombatants and combatants alike, with civilian casualties for the first 10 months of this year running 20 percent higher than the same period a year ago, according to the most recent figures available from the United Nations. Insurgents are blamed for about three-quarters of civilian deaths, but Western troops inadvertently cause some as well.

Fourteen dead is an unusually high toll for a single IED blast, but not unheard of. Any form of inexpensive public transport is usually packed with whoever can squeeze aboard, and the consequences of hitting a roadside bomb reflect that overcrowding.

The number of wounded - four - was smaller because the bomb was powerful enough to kill outright rather than injure. Over the last year, the insurgents have planted larger and larger IEDs.

Daoud Ahmadi, a spokesman for the Helmand government, said the explosion occurred on the highway to Kandahar, the south's main urban hub in the neighboring province of the same name.

Together with Kandahar, Helmand has been the scene of some of the year's worst fighting. It started in the town of Marjah, site of a U.S. Marine-led offensive that began in February and continued for months. In the autumn, the Marines took over from British troops in one of Helmand's most violent districts, Sangin. The British suffered heavy casualties there; so have the Marines. Nahr-e-Saraj lies just to the south of Sangin.

Thursday's bombing was condemned by Afghan President Hamid Karzai, who termed it "antihuman . . . brutal and ignorant."