A bomb killed at least seven security guards protecting a dam in western Afghanistan Tuesday, an official said, dpa reported.
"All seven guards of the Public Protection Force were killed when their vehicle hit the roadside bomb in Chesht-e-Sharif district," said Moheyuddin Noori, a spokesman for Herat province's governor.
The unit is a government enterprise that guards private and government infrastructure, organizations and institutions.
Noori said the guards were protecting the 200-million-dollar Salma hydroelectric dam project being built by the Indian government.
Earlier this year, intelligence agents foiled a plan to bomb the dam, and seized more than a ton of explosives.
Local officials blame neighbouring Iran and Pakistan for trying to obstruct the construction.