Pakistani officials say they have arrested 35 people in connection with the suicide car bombing Tuesday that killed three American military trainers and four Pakistanis in northwest Pakistan.
Police official Naeem Khan said Thursday that Pakistani police are questioning the suspects to determine who orchestrated the attack in Lower Dir district. A spokesman for the Pakistani Taliban has claimed responsibility.
Three of the Pakistani victims were schoolgirls, and the fourth was a local soldier. More than 60 others were wounded in the blast.
Meanwhile, Pakistan's army says its forces are continuing an offensive against militants in the Bajaur tribal region and have killed 12 fighters in the last day. Troops are using helicopter gunships and artillery to force the militants from their stronghold in Damadola.
Tuesday's attack in Lower Dir district hit a convoy carrying American military trainers who are helping to teach Pakistan's paramilitary force known as the Frontier Corps in counterinsurgency tactics. A district police officer told VOA that militants detonated the bomb just as the soldier's convoy passed a school in the former Taliban stronghold.
U.S. officials say the Americans were traveling with Pakistani paramilitary forces to the opening ceremony of a girls' school that recently was renovated with U.S. assistance.
Some information for this report was provided by AP.