Separately, four Afghan police were killed and three wounded when a rocket-propelled grenade hit their vehicle in the southern Logar Province on August 4.
The Taliban have stepped up attacks against the Kabul government and its Western backers mostly in the south and southeastern provinces of Afghanistan in the last 18 months.
In other news in Afghanistan, Taliban insurgents say there is still no agreement on where to hold direct talks with South Korean diplomats seeking the release of 21 of their countrymen kidnapped more than two weeks ago.
A South Korean delegation was in Ghazni Province, southwest of Kabul, seeking face-to-face talks with the kidnappers.
The Taliban want negotiations either in areas they control or with United Nations guarantees for their safety if held elsewhere.
Taliban spokesman Qari Yusof Ahmadi said today that talks and contacts are still going on to decide on a venue for talks.