The Afghan Intelligence, National Directorate of Security (NDS), said Mawlavi Nematullah was arrested together with his two colleagues from Lashkargah city by the intelligence operatives.
A statement by NDS said a Dshk heavy machine gun was also seized along with various other types of weapons, ammunition and explosives from the detained militants.
The Taliban militants group has not commented regarding the report so far.
The Taliban-led insurgency has been rampant since the group announced its spring offensive earlier in April this year and vowed to carry out more attacks.
In the meantime, the Afghan forces have also stepped up counterterrorism operations by launching an annual offensive to suppress the activities and plans of the group.
Earlier, the Afghan intelligence operatives confiscated at least 3,000 kgs of explosives as the group was looking to transport them to Kabul city for a series of attacks.
NDS said the Taliban militants were looking to use the explosives to conduct attacks during the Ramadan and Eid days.