Provincial governor spokesman Aziz Ahmad Azizi said the incident happened last night in Maiwand district as a result of the explosives planted in a tunnel below the military base.
Azizi confirmed that casualties have been sustained to Afghan forces but said the exact number was unknown.
Meanwhile, a security source who wished not to be named told Ariana News that the base was sheltering 30 soldiers. He added that five soldiers were killed and others were injured.
A spokesman for the Taliban militant group claimed that 35 soldiers have been killed and five others were wounded in their attack.