On the crumbling mountainside that leads up to the Afghan border are three painted words: "Go back America!" Across the gaping gorge that divides the two countries, tiny figures shift in the fading sunlight along the mountain ridge. They are fresh Taliban reinforcements, whose guns and heavy mortars are nearly invisible to the human eye.
Long known as a crucial gateway between the West and the South Asian sub-continent, the peaks and crags of the Khyber Pass - and the people that live there - present one of the greatest obstacles to US military planners now considering how to get foot soldiers on the ground inside Afghanistan.
For some 18 million Pashtun tribesmen, villagers, and refugees on both sides of this border, blood is thicker than politics. Villagers may have been radicalized by two decades of war, but perpetual strife has also strengthened the traditions that bind them. If the US military is to succeed in its apparent mission to find suspected terrorist Osama bin Laden and his associates, it will have to be extremely sensitive to these traditions, Pakistani historians and Pashtun locals caution.
One of the most common concerns, voiced both by Afghan refugees and Pakistani Pashtuns, is the sanctity of their sense of hospitality. "If you want Osama, then you will have to kill us all," says Mohammad Arif, a Pakistani villager strapped with a pistol and standing beside a fruit stand. "If we have a guest in our house, we will keep him in our house. You must give us proof before you get him. We are a free people."
Afghanistan's 10 million Pashtuns are the country's majority, with another 8 million in Pakistan. They have fought among themselves for centuries, but throughout history, nothing has done more to unite them than a common enemy.
During three Anglo-Afghan wars between 1839 and 1919, British troops met some of their fiercest resistance here at the Khyber Pass. In 1878, Afghan fighters sniped at British forces and ambushed them at every turn in the narrow, winding road. The Afghans' superior guerrilla tactics prevented the British from ever gaining full control of Afghanistan.
That fighting was a precursor to what the Russians would face all across the same jagged peaks and valleys 100 years later. Even when they used heavy guns to blast away at the face of a mountain, the Afghans would often pop up again, aiming their homemade rifles from a nearby peak.
Over the weekend, truck drivers - the only humans currently allowed to leave Afghanistan - said the Taliban is distributing guns and warning of an imminent attack by the "infidels." Meanwhile, the villages on the Pakistani side were doing a brisk business in light machine-guns, small mortars, hand grenades, and rocket-propelled grenades.
Already, local newspapers in Peshawar are reporting the movement of hundreds of Pashtun religious students into Afghanistan, allegedly to fight the Americans. Some of these youths, the papers report, are aligned with the Harkat Mujahideen, which Pakistani officials believe lost two-dozen fighters when US fighter bombers struck bin Laden bases in August 1998.
While US forces will face hostility from Pashtun tribesmen on both sides of the border, the intimate relations may also provide an invader with a double-edged sword.
"It is true that enmity with one Pashtun translates into enmity with the entire tribe," says Ghulan Taqi Bongash, chairman of the history department at the University of Peshawar. "But with the Pakistani government agreeing to help the US with intelligence, Washington may have at least one ace in the hole. Tribal connections are going to be a key to finding out exactly where Mr. bin Laden is hiding out."
When the CIA was funding the Afghan uprising against Soviet occupation in the 1980s, Pakistan's Inter-Services Intelligence directorate (ISI) was key. So were Pashtun connections.
Brig. Mohammad Youssaf, responsible for training and operations of mujahideen from 1983 to 1987, took great pride in telling associates about his Pashtun-Afghan bloodlines. This was immensely useful to CIA officials, who could rely on Pakistani officials to do much of their "fieldwork" for them, according to John Cooley, author of the book "Unholy Wars: Afghanistan, America and International Terrorism."
When the CIA left, the Pakistani Pashtuns working in the ISI kept up their links inside Afghanistan and eventually helped orchestrate the rise of the Taliban, which now staffs almost all its major posts with Pashtuns. Today, with Pashtun informants deep inside Afghanistan, information about the movements of the several thousand Arab associates of bin Laden is already well known, say local journalists and officials in nearby Peshawar.
But Prof. Bongash warns that to win the ultimate struggle against terrorism, the US will have to also win the hearts and minds of the Pashtun people.
"The Afghans, contrary to some legends, are not supernatural fighters," he says. "The Taliban is already running short on international support and food. The West will have to quickly fill the void by giving massive relief to the refugees and satisfying the tribesmen on both sides of the border."
For now, Afghans and Pakistanis are extremely wary of US intentions. "I am not a Taliban, but if America attacks, we will all stand with the Taliban," says Jumagul Adel, wearing a purple beret and standing in a crowd of refugees anxious to talk with a foreigner. "And be careful you don't kill innocent civilians, because we know your bullets don't have eyes of their own."