There is worry that violent militants inside Pakistan could destabilize the country.
American officials want Pakistan to intensify its fight against those militants because they complicate the U.S. war in Afghanistan. Pakistan has repeatedly driven out the Taliban from tribal zones near its border with Afghanistan. But the militants won't stay beaten.
Last month, militant violence struck a district along the edge of Pakistan's tribal region. The target was Shabqadar Fort, a 19th century structure that serves as the headquarters for Frontier Constabulary troops, a paramilitary force recruited among the local ethnic Pashtun tribes. They're supposed to keep order when a situation grows too violent for the police.
Several hundred recruits were going on leave, and they crowded around the fort's front gate. As they were boarding buses, a motorcycle rider rolled toward them down the street. The attacker blew himself up, killing nearly a dozen people. More were wounded.
As constables rushed to the gate to help, a second attacker was watching.
Law enforcement official Usman Ijaz says that second attacker blew himself up inside the mob that was trying to help the wounded. The attacker had "filled the bomb with ball bearings" to kill more people.
After the second explosion, 79 lay dead.
Base commander Irshad Alam said the recruits "were lying there just like sheep and goats. I was picking them up with my own hands."
He said "the image kept replaying in front of my eyes."
The experience left Alam demoralized for more than two weeks. "Why are our children being killed?" he asks. "Maybe it's a punishment from God because our behavior hasn't been very good."
'There's No Such Thing As Victory'
Shabqadar Fort has stood against tribal uprisings throughout its history. Peacocks and other birds stroll around the grounds. It's a peaceful place in the middle of a war.
"Things may look normal," Ijaz says. "But they're not that normal."
In recent years, the area has become more secure after Pakistan's regular army deployed in the province. But militants keep filtering back.
Since the bombings, the front constables aren't even sure about the people in the bazaar right outside their gate.
Ijaz says it's hard for the army to find the manpower to be everywhere at once.
"They clear one area," he says, "they go to another area."
"We have to do a whole lot of operations at a time."
About 140,000 troops are deployed in the tribal zones and in the adjacent province. Gen. Asif Yasin Malik is the region's regular army commander. He claims his troops are able to hold the ground they win from militants, but that those efforts limit their ability to strike elsewhere.
"There's no such thing as victory," he says. "It's always relative."
His goal is to establish enough security that civilian officials can work to build infrastructure and encourage development.
After the bombing at the Frontier Constabulary base, the surviving recruits were sent out to their new units across the district. More recruits arrived for their six-month training course, along with experienced paramilitary troops.
They're all preparing for the next phase of a conflict among their tribes.
Ijaz knows it's a region where tribal loyalty is extremely strong.
"Yes, they are facing this problem" of divided loyalties, he says. "In some cases, it helps them." If a family has a son in the security services, it helps to have another with the militants.
Anayatullah is a member of the Mehsud tribe, whose leaders have been at the heart of the rebellion. He's been a member of the constabulary forces for 24 years.
"We are very worried about this," he says. His family in the tribal zone of South Waziristan faced so many threats they had to move.
Pakistan has seen conflict before, but rarely anything like this. The war could take years to resolve.