Afghan intelligence -- the National Directorate of Security -- and Afghan national army soldiers made the discovery in Chesht and Pashtun Zarghoon districts, said province spokesman Mohiuddin Noori.
Noori said the explosives were imported from outside the country and were among the most dangerous and destructive of their kind.
The Afghan national security council had previously expressed concern regarding neighboring countries interfering in the construction of the Salma water dam, Khaama Press reported.
Construction of the dam was expected to be completed within three years, but the deadline has been delayed due to instability in the region.
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