This is the new Taliban country — a no-man's land filled with fighters-for-hire, drug dealers, warlords and assorted criminals.
In the towns of Pakistan's Waziristan region, armed Islamic militants now hold sway, governing like a state-within-a-state. Some call it the heart of "Jihadistan" — from this haven, Taliban and al-Qaida fighters launch attacks over the border, inside Afghanistan, then regroup back in Pakistan.
And, increasingly, they're using an al-Qaida tactic: Suicide bombers, often trained and equipped by recruiters in Pakistan.
"They'll use some of the mentally handicapped," says Maj. Jason Warner, an intelligence officer. "We've seen some of that. We've seen some of the physically handicapped also used."
Compounding the problem, much of what happens inside Waziristan and the rest of the tribal belt goes unreported. Foreigners are not allowed beyond a certain point. And even Pakistani journalists who aren't from the area enter at their own risk.
Inside the sanctuary, NBC News found cleric Faqir Mohammed, an al-Qaida-linked fugitive. He spoke openly about his mission.
"Our enemy is the infidels," he said. "And we'll fight them until they leave Muslim land."
Mohammed has sworn allegiance to al-Qaida leaders Osama bin Laden and Ayman al-Zawahri, both believed by some Taliban experts to be hiding here as well, protected by the militants.
"They are the threat," says Taliban expert Ahmed Rashid. "It's taken four years for the Americans to wake up to this reality."
Pakistan President Pervez Musharraf is under increasing U.S. pressure to clean out the sanctuary. But three years of military offensives, by some 80,000 troops, have failed.
Another strategy that hasn't worked: pulling Pakistani troops back in a truce with some local tribes. That's led to even more cross-border attacks.
And, as the Taliban haven thrives, winning America's forgotten war, next door in Afghanistan, becomes even harder.