KHOST, Afghanistan -- Gazing out at the wheat fields, a haggard police chief pointed to the distant goat paths leading from Pakistan's territory of North Waziristan. Known here as "Osama bin Laden's children" or "the walking dead," nearly two dozen suicide bombers entered Khost province over those paths in the past year.
"The only thing left of them after they are done is two feet and a lot of skin," said Maj. Bismullah, a local police chief who, like many Afghans, uses only one name. "If we get a finger, we have to send it to Kabul to analyze the prints."
Orphaned by war and schooled in anti-American religious madrassas, the bombers often smile for a final video testament in Pakistan before walking or riding to their deaths in Afghanistan. As new explosives technology and tactics from the war in Iraq arrive in this remote corner of South Asia, suicide bombing attacks in the past 12 months have more than quadrupled from fewer than half a dozen in the previous year.
At least some of the bombers cross the border with a blessing from Ayman al-Zawahri, bin Laden's bespectacled ideological lieutenant, said Lutfullah Mashal, a senior intelligence official with Afghanistan's National Security Council.
Afghan and U.S. officials say the bombers are trained in Waziristan, a tribal-administered border region of Pakistan. Several weeks of reporting along the rugged border suggests that al Qaeda and its affiliates are regrouping with charitable funds from Gulf Arab states, assistance from rogue elements of Pakistan's intelligence services and profits from the heroin trade.
Pakistan, which sanctioned U.S. bombing raids on suspected al Qaeda hide-outs last year, has all but retreated from its effort to fight the Taliban and al Qaeda in border areas, say Western diplomats.
Instead, it has signed peace deals last year leaving enforcement of local security to pro-Taliban elders in North and South Waziristan. A similar deal was concluded last week for the similarly lawless Bajaur district farther north.
Mr. Mashal criticized Pakistan's embattled President Pervez Musharraf for signing the latest deal. After the signing, Taliban leaders warned Pakistani security forces and U.S. forces to "avoid interference" in their internal affairs.
In sunny Khost province, where the governor's guards stand at attention with fresh flowers in their hair, the spate of suicide bombings has altered shopping habits and angered residents.
Suicide bombing was unheard of during the long war against Soviet forces in the 1980s, when locals prided themselves on their skill in shooting down Soviet helicopters, rows of which still line the edge of the airport here.
As elsewhere in the Islamic world, al Qaeda is usually a facilitator of terrorism, rarely the direct instigator. Bin Laden's operatives exploit anti-American sentiment within home-grown Islamist groups and dispatch young men over the mountains toward martyrdom.
Al Qaeda and Taliban leaders in nearby Pakistani community of Miram Shah, mimicking similar martyrdom celebrations in the West Bank and parts of the Arab world, throw lavish parties for the families of the suicide bombers.
U.S. soldiers in the 82nd Airborne Division have trained in advance of their deployment to spot suicide bombers, said the unit's combat operations chief in Khost, Lt. Col. Scott Custer. "We look for gestures in their eyes," he said.
Col. Custer said it was "not blind luck" when a young U.S. sergeant last month spotted a bomber disguised as a surgeon when he arrived at a dedication ceremony for the recently renovated Khost hospital.
"He spotted his nervousness and shouted for him to halt," said the colonel, who witnessed the attack.
The Afghans had time to scatter and the sergeant, later rewarded for his bravery, tackled the bomber and shot him once through the leg before retreating as several U.S. officers riddled the bomber with bullets.
In his death throes, the bomber was able to clasp his hands together and detonate his explosives, causing minor injuries to the tackler and bystanders.
Afghan and U.S. officials now think an accomplice dropped off the suicide vest at the hospital before the ceremony.