Kandahar, Afghanistan  - One US soldier under NATO command and 14 Afghan civilians, including women and children, were killed in three separate roadside bomb explosions just a week before Afghanistan's presidential election, officials said Thursday.

Eleven civilians, including two women, were killed when their vehicle was blown up by a roadside bomb in the Gerishk district of the southern province of Helmand, Daoud Ahmadi, spokesman for the provincial governor, said.

A six-year-old child, whose parents were among those killed, was wounded in the blast that took place in the Spin Jomat area of the district on Wednesday, he said.

Ahmadi held "enemies of Afghanistan," a term often used to describe Taliban militants, responsible for the attack. The Taliban rely heavily on the use of roadside attacks as part of their insurgency.

Three other children were killed in the neighboring Kandahar province, also on Wednesday, in a similar roadside bomb blast, Mohammad Shah Farouqi, a police official in the province, said.

The children were playing in an area just outside Kandahar city on Wednesday afternoon when the blast occurred, he said.

Meanwhile, a US soldier was killed on Wednesday when the vehicle he was travelling in was hit by a roadside bomb, the NATO alliance said in a statement.

The statement did not provide more details, other than quoting Captain Jon Stock, a US spokesman, who confirmed that the deceased was a member of the US forces.

Taliban militants have intensified their attacks in the country in recent weeks, raising concerns among Afghans that the landmark August 20 presidential election would be overshadowed by violence. (dpa)