A roadside bomb killed two women in southern Afghanistan, authorities said Saturday, the latest civilians killed by one of the Taliban's most effective but also indiscriminate weapons.

The women were walking along a road in the southern province of Helmand when they stepped on the buried explosives Friday, the Afghan Interior Ministry said in a statement.

Roadside bombs are a common Taliban weapon targeting government and international forces, but they also kill dozens of civilians each month. The homemade explosives accounted for half of the about 1,500 civilian deaths in the first six months of last year, the U.N. estimates.

NATO also said Saturday that a coalition service member died in western Afghanistan of a "non-battle-related" injury. A coalition statement gave no other details.

The U.S. has been working to start negotiations with the Taliban to end the decade-long war, and the insurgents last week said they would open a political office in the Gulf state of Qatar to prepare for eventual talks.

However, the militants said later that their willingness to talk doesn't mean they will not stop fighting. The Taliban ruled with a harsh interpretation of Islamic law for five years before being driven from power by U.S.-led forces in 2001.