One of the latest US hunts for fleeing Al Qaeda members focuses on a string of mud-brick, highland villages near Zarmat in the country's east.
But, as with almost any other issue in Afghanistan, tribal differences are getting in the way.
Local Pashtun tribal and militia leaders say that Northern Alliance troops, who hail mostly from the Tajik and Uzbek ethnic groups, are using the US hunt for Al Qaeda as an excuse to break into Pashtun homes and steal trucks. They say that if the Americans had asked them for help in the search, they would have provided it.
"We believe that the US does not want to create problems around here, but the Northern Alliance forces are guiding them in the wrong direction," says Mohamad Naim Farouk, the Zarmat security chief. "The proof of the problem for the Americans is that they still haven't found one Al Qaeda member in our area."
In a Monday raid in a nearby province, US forces arrested four men for questioning on the whereabouts of former Taliban Frontier Affairs Minister Jalaluddin Haqqani. The Taliban, which hosted Osama bin Laden and members of the Al Qaeda terrorist network, was driven from power in Kabul late last year after a US bombing campaign.
After the fall of the Tora Bora Al Qaeda camp some 50 miles north of Khost, hundreds of Al Qaeda members fled south, following camel caravan routes over the mountains here into the Pashtun heartland. In this area, split between Taliban sympathizers and traditional "royalists" who back the return of King Zahir Shah, the Arab and Afghan militants have found refuge and, sometimes, safe passage to points further south or outside Afghanistan.
On Sunday, thickly bearded US special forces spread out into the parched fields near Zarmat and barked terse orders into their headsets. Northern Alliance forces pushed open a door and forced their way into a home, some of them taking up firing positions, even as the US soldiers guiding their actions stood by - looking almost relaxed. When Pashtun villagers complained that Northern Alliance forces have been seizing cars and weapons, reinforcements leaped from jeeps. No bullets were fired, however.
"The situation is a little confusing," says a US special forces officer, walking over to the window of a reporter's car. "It is hard to know who is who."
Pashtun tribal leaders say that the special forces can't hope to ever learn "who is who" until they stop sending Uzbeks and Tajiks into Pashtun villages. The leaders complain that the searches are a violation of Pashtun tribal tradition, particularly the privacy of their women, who go unveiled inside their homes.
"The enmity and differences between us and the Northern Alliance are far worse than our political relations," says Aman Ullah Khan, the ethnic Pashtun Minister for Tribal and Frontier Affairs. "They treated us like slaves when they ruled Kabul in the 90s, and they want to treat us like slaves again."
Two other Pashtun leaders in Zarmat warn of an imminent "uprising" if the searches continue without consultation with tribal chiefs.
In the Monday raid, in nearby Khost Province, four US helicopters swooped down on the home of brothers Agabe Gul and Kabir Din, whose home had been bombed in late November as Mr. Haqqani, the Taliban's most powerful military leader, ate with the family.
Twenty-nine people had been killed in that air raid, which Mr Haqqani escaped the same night by truck with only an injured arm, say villagers.
Agabe Gul, an aging red-bearded Pashtun, came to the governor's house in Khost on Monday to complain that US soldiers had taken away four members of his family.
Several eyewitnesses described what sounded like a classic commando raid, with men scaling mudbrick walls and then blasting metal doors down with grenades before ransacking the home for clues as to the whereabouts of Mr. Haqqani and his associates. Women and children were kept in the courtyard during the search, said witnesses.
"All of our women and children are in tears now, saying that the Americans have taken the four men away to be slaughtered," says Mr. Gul.
A regional military commander and Pashtun royalist, Sakhi Jan Wafadar, backed up the old man's account and said the family's only "sin" had been offering Haqqani a Ramadan meal last November, as tribal custom dictates.
Abdul Satar, a former Taliban militia member and now a Pashtun militia commander, acknowledges that there are plenty of Al Qaeda fighters still in the area. "They are up there - over in the mountains," he says, pointing to a ridge running in the direction of the southern city of Kandahar. "We are keeping this checkpoint here, ourselves, just to catch the Al Qaeda cells if they pass through here."
Even as he speaks, a tall, turbaned man with a face strikingly similar to that of Osama bin Laden walks past. The man has a haughty, disdainful air about him. The militia commander says: "The problem is that it is so difficult - even for us - to tell an Arab when we see one."
Royalist Pashtun leaders close to Afghanistan's new leader, Hamid Karzai, insist that the US military must adjust its search-and-seize operations to involve Pashtun villagers.
Aman Ullah Khan, Kabul's minister for tribal and frontier affairs, says: "If the special forces seek our help, they can both bomb from the air and send in ground troops. We want them (Al Qaeda) killed, too, but if the US wants a war, it must choose the right friends."
Mr. Khan insists that if the US raids continue without Pashtun consultation, sympathy will grow for the Taliban and Al Qaeda.
"If the US military attacks the problem in the way they are now, the villagers will be sure to give safe passage to all their 'guests,' " he says. "It will be a losing game, and, in the end, Al Qaeda cells will escape the same way they did in Tora Bora."