Suspected Taliban militants were holding a group of around 30 Pakistani boys on Friday after luring them into Afghanistan and kidnapping them, Pakistani officials said.
The insurgents initially seized around 40, but those under 12 were released Friday and traveled back to their villages in the Pakistani border region of Bajur, said its top political official, Islam Zeb.
It was unclear why they were kidnapped, but militants often target people from tribes who oppose _ or do not support _ them.
The boys, aged between 10 and 15, went to Afghanistan's Kunar province on Thursday after a man invited them to play in a river there, said Zeb and Abdul Haseeb Khan, another official. They were from villages very close to the border.
Zeb said elders were negotiating with the captors to free all the boys.
In Afghanistan, Kunar police said they are investigating but have no reports of such an incident.
In recent months, there have been several bloody cross-border raids by militants from Afghanistan into Pakistan.
Pakistani officials have said the attackers were militants who had fled its army operations in Pakistan and were using Afghan soil as a safe haven.
Zeb said the militants holding the boys were from a group that used to operate in the Bajur region.