DAVUDZAY, Afghanistan (AP) _ Troops with powerful rifle scopes scanned mountain ridges for elusive, black-clad Taliban infiltrators. Afghan soldiers, hit by a roadside bomb, pressed on into the valley. U.S. Special Forces swept through the sinister alleys of its main settlement.
The strike, carried out by about 200 American and Afghan government forces, was supposed to sever a major insurgent infiltration and supply route from neighboring Pakistan to Islamic fighters deep in Afghanistan.
But the attack didn't work _ an object lesson in why 47,000 U.S. and NATO forces are struggling to contain a resurgent Taliban movement.
Field officers say eradicating fighters who cross the porous 1,470-mile border is like trying to drain a swamp when one cannot shut off the streams feeding it. Pakistan's failure to dam those streams has deepened the five-year-old conflict, they say.
``Stopping the infiltration is not the only way we are going to win this war, but it's a very key factor,'' said Capt. Samuel Edwards, who led U.S. Army troops in a recent drive into the Davudzay mountain bowl in the southeastern province of Zabul.
The Zabul routes are just a fragment of a vast cross-border network, reminiscent of the Ho Chi Minh Trail of jungle tracks and secret roads that carried Vietnamese communist troops and equipment to battle.
NATO ``will never control the border without greater control of the border areas by Pakistan and greater coordination and cooperation between Pakistan and Afghanistan,'' Gen. John Craddock, the current NATO commander, said recently in Washington.
Taliban fighters and al-Qaida militants converged on the frontier after U.S.-led forces drove them from Afghanistan in 2001. Pakistan is now under greater pressure to act _ particularly after the U.S. military last fall reported a threefold increase in cross-border attacks into eastern Afghanistan.
In January, John Negroponte, then U.S. national intelligence director, voiced concern about the Taliban finding sanctuary in Pakistan, and U.S. officials cautioned that al-Qaida could be regrouping along the frontier.
Edwards says his unit, a company of the 4th Infantry Regiment, has done well in mapping the trails between Pakistan's borderlands and into Zabul.
``We've kind of connected the dots. But we're never going to stop it completely. 'Disrupt' is the word I would stick with,'' he says.
The company's intelligence officer, Capt. James Kretzschmar, says most insurgents enter Zabul through the Maruf Valley after training near the southwestern Pakistan city of Quetta. Former NATO commander Gen. James L. Jones said earlier that Quetta remains the Taliban's main headquarters.
Once inside Zabul, some of the Taliban and foreign Islamic fighters are believed to head straight down a highway to Kandahar province while others make for Zabul's rugged northwestern districts and onward into the Taliban heartland in the south, where the most intense fighting is now taking place.
``It's an annual cycle. It's weather-dependent,'' says Kretzschmar, of Albany, N.Y.
When the snows melt in the spring, men, weapons and supplies begin moving in small groups, often along mountain ridges, on donkeys and motorcycles, he says.
Those already in Zabul blend in with villagers during the winter in places like the Davudzay bowl.
Pakistan maintains that the insurgency is primarily an Afghan problem, fueled by domestic frustration over poverty and dissatisfaction with the Afghan government. It says it has deployed 80,000 soldiers to stop Taliban supporters crossing from Pakistan to fight _ far more troops than marshaled by Afghanistan, the U.S. and NATO on the other side.
``We are trying to ensure that the support the Taliban have here does not go across,'' said army spokesman Maj. Gen. Waheed Arshad. ``Movement across the border has reduced by a great extent.''
Also, some Taliban leaders have been arrested, and Pakistan has started building a fence along 177 miles of frontier.
NATO spokesman Col. Tom Collins in Kabul said Pakistan had ``done pretty well,'' particularly against al-Qaida. He said that sealing the border was virtually impossible, although coordination was improving among Pakistani, Afghan and NATO forces.
U.S. officers on the ground in Zabul see little change. And Afghan officials say elements in Pakistan's powerful ISI intelligence agency flagrantly support the Taliban.
``I can give the Pakistanis a list of the Taliban that are coming into my province,'' Zabul Governor Dalbar Ayman said angrily in an interview. ``The world found their address in Pakistan, so why couldn't the Pakistanis have arrested them years ago? The ISI knows every village, every district, every individual.''
Pakistan strongly denies these charges. But nonetheless, Taliban fighters are coming through.
Edwards, of Jonesboro, Ga., plots their precise trail in the area under his command: Larzab, Tangay Kalay, Davudzay, Myrah, the Chalakoor Valley, Mizan.
Above Tangay Kalay, the machine guns of Staff Sgt. Leon Baudoux's squad were trained on the hamlet below and the mountain pass sloping southward into the Davudzay bowl.
``They are pretty good at hiding behind rocks and popping up every once in a while to spray (shoot) and pray,'' said Baudoux, of Saginaw, Mich.
But as the 12-hour operation proceeded past sheer rock faces and cascades of boulders, no insurgents popped up. Only four curious shepherd boys approached Baudoux's squad.
``Our problem is that it takes us too long to move from point A to point B. All it takes is one guy looking out through a window in a bazaar and calling in, 'They're coming,''' said 1st Lt. Jason Cunningham.
And that's what happened. As a long column of Humvees snaked around hills on its way to trap the Taliban, rumbling through villages past impassive bearded men and waving children, interpreters monitoring insurgents' radio transmissions could hear them warning each other of the Americans' approach.
The militants lay low or fled.
``The plan was solid,'' said Baudoux. ``But there was no enemy. They knew we were coming.''