The elite law enforcement agency’s spokesperson Mufti Mahmud Khan said the 16-year old Rezaur Rahman Fahim was detained around 1am on Friday at the Jatrabari check post.
He had the bombs in a bag he was carrying.
Fahim is also a key suspect in the bombing of a procession led by Shipping Minister Shajahan Khan in Gulshan on Feb 16, the official added.
BNP chief Khaleda Zia had called for an indefinite transport blockade on Jan 5, demanding interim polls under a non-partisan government after police prevented her from leading an anti-government protest rally.
More than 125 people have been killed, mostly from burns, in violent bombings, arson, firebombing and vandalism of vehicles and private properties that have marked the agitation.
A number of BNP leaders were also killed in accidental blasts while making bombs.
Several workers’ organisations have marched toward the BNP office since the blockade began in a bid to make the BNP chief to call off the violent programmes.
On Feb 16, at least 11 people were injured when handmade bombs were detonated at a protest march led by minister Khan.