KANDAHAR, AFGHANISTAN — A summer of heavy fighting during which Western military leaders had hoped to seize the initiative from Islamic militants has instead revealed an insurgency capable of employing complex new tactics and fighting across a broad swath of Afghanistan.
Over the last three months, insurgents have exacted the most punishing casualty tolls on Western forces since the Afghan war began nearly seven years ago. Numbers of foreign troops killed have exceeded U.S. military deaths in Iraq.
As Washington prepares to increase troop levels and Defense Secretary Robert M. Gates paid a visit, militants have created a palpable sense of encirclement in Kabul with a series of small but highly symbolic attacks near the capital. They have reaped a propaganda bonanza from accidental killings of civilians by foreign forces and undercut reconstruction efforts by targeting aid workers.
Meanwhile, the vast narcotics empire presided over by the Taliban has continued to flourish, its profits helping to ensure a flow of cash and weaponry.
"In all, we feel that things are going very, very well for us," said a Taliban field commander in Kandahar province whose men fought hit-and-run battles with Canadian and British forces during the summer, the season when fighting is most intense. "And what is more, time is on our side."
Militants have suffered losses of their own. NATO- and U.S.-led forces, which total nearly 65,000 troops, say they have killed hundreds of insurgents over the summer. Dozens of veteran mid-level commanders have been arrested or killed, depriving insurgents of "what could best be described as their bank of institutional expertise," a U.S. military official said.
At the same time, though, militants have demonstrated new strength, sophistication and ambition, particularly in eastern Afghanistan. A roadside blast there Wednesday killed four foreign soldiers and an Afghan. The victims were not identified, but most of the international troops there are Americans.
"When you have six years of combat experience, you get steadily better," said Anthony Cordesman, a fellow at the Center for Strategic and International Studies.
Western field commanders readily acknowledge that the Taliban and loosely allied militants learn from failures as well as successes. When Taliban fighters noticed that Western forces were jamming the signals insurgents used to detonate roadside bombs, they switched back to pressure plates that would be set off by the weight of a passing convoy.
Through the careful choice of targets, tactics and technology, the militants appeared to frequently catch Western commanders and their Afghan allies by surprise. They have defied expectations that they would avoid full assaults on major Western bases.
That has led to some jarring setbacks.
In June, the Taliban orchestrated a spectacular prison break here that set hundreds of insurgents free. A multi-pronged assault on a remote, just-established U.S. outpost killed nine Americans in July. In August, an ambush killed 10 French troops -- and set off impassioned debate in yet another NATO country over the efficacy of the Afghan mission.
In large swaths of the countryside, insurgents have been able to intimidate local officials into cooperating, in part because President Hamid Karzai's government is perceived to be corrupt and inefficient.
"Once, people would look to the government for justice," said Abdul Qadoos, a businessman and tribal leader in Kandahar province. "Now they go to the Taliban."
Like their counterparts in Iraq, Western military officials speak in frustration of achieving success in one area, only to see the militants pop up in another. Marines claim credit for choking off an infiltration route from Pakistan in Afghanistan's south over the summer. But during that period, the east, where long-time insurgency leaders are joined by Islamic militants focused on a global conflict with the West, became a caldron of violence. U.S. and NATO officials say fighters can move freely across the frontier from Pakistan's tribal areas.
American forces have stepped up strikes, mostly airborne, against militant targets in Pakistan. However, military officials and analysts say the insurgents may become less reliant on rear bases in Pakistan because they have been improving their infrastructure in Afghanistan. For example, they have created large networks of safe houses close to Kabul.
Western troops face the conundrum that any conventional army confronts in a guerrilla war: Insurgents appear victorious merely by staying in the fight.
"The kinds of strikes they make are useful in providing a perception of insecurity, and in getting some NATO countries to change their cost-benefit analysis of the conflict," said Seth Jones, a counterinsurgency expert at Rand Corp.
Even senior U.S. military commanders acknowledge the insurgents' resourcefulness and resilience.