A suicide blast near one of Pakistan's two main border crossings with Afghanistan has wounded at least 22 people, including several members of the security forces.
Monday evening's attack prompted Pakistani authorities to swiftly suspended all traffic at the southwestern Chaman post.
Officials said personnel of the paramilitary Frontier Corps were heading to the border crossing when a suicide bomber ambushed their vehicle and blew himself up near a busy public spot.
Splinter group takes credit
A splinter Pakistani Taliban faction, Jamaatul Ahrar, quickly claimed responsibility for plotting the attack.
Pakistani authorities said body parts of a teenage boy have been retrieved from the site and investigators are trying to determine whether he was the bomber.
Islamabad alleges fugitives of the outlawed JuA extremist outfit use sanctuaries on Afghan soil to orchestrate terrorist attacks against Pakistan, accusing Kabul's intelligence agency of supporting the activity.
Afghan officials deny the accusations.
Torkham crossing bombed last week
Last week, a bomb explosion at the busiest northwestern Torkham border crossing injured several Pakistani soldiers, prompting authorities to suspend all movement across the frontier for a couple of days.
Landlocked Afghanistan relies on the Chaman and Torkham crossings for transit and trade with Pakistan and other countries.
Military clashes between the two countries and militant attacks on Pakistani territory have led to repeated closures of the two crossings, inflicting heavy financial losses on trading activity, say Afghan traders.