"Taliban key commander Mubarak Shah alias Jahan along with three of his men was busy in making mine in a house in Narai district on Friday night when the device exploded accidentally, killing all the four on the spot," Humat told Xinhua.
A child was also injured in the blast, the official added.
Taliban militants, he said, often use the homemade mines as roadside bomb to target security forces convoys.
Taliban militants haven't commented.
XINHUA/MNA