Pakistan ? Authorities have detained 35 suspects in connection with a suicide car bombing that killed three U.S. soldiers in northwest Pakistan who were part of a little-publicized mission to train local forces to fight the Taliban and al-Qaida, police said today.

The killings Wednesday were the first known U.S. military fatalities in nearly three years in Pakistan’s Afghan border region, drawing attention to a training program officials rarely discuss because of opposition here to American boots on Pakistani soil.

The blast also killed three girls at a nearby school and a Pakistani paramilitary soldier traveling with the Americans. Two more U.S. soldiers were wounded, along with about 100 other people, mostly students at the school. Several were left trapped, bloodied and screaming in the rubble.

“We launched a massive search in the area yesterday, and now about 35 suspects are in our custody and we are questioning them in an effort to trace those who orchestrated the suicide attack,” police official Naeem Khan told The Associated Press today. “God willing, we will capture those responsible for this carnage.”