WASHINGTON — Senior Taliban leaders, showing a surprising level of sophistication and organization, are using their sanctuary in Pakistan to stoke a widening campaign of violence in northern and western Afghanistan, senior American military and intelligence officials say.

The Taliban's expansion into parts of Afghanistan that it once had little influence over comes as the Obama administration is struggling to settle on a new military strategy for Afghanistan, and as the White House renews its efforts to get Pakistan's government to be more aggressive about killing or capturing Taliban leaders inside Pakistan.

American military and intelligence officials, who insisted on anonymity because they were discussing classified information, said the Taliban's leadership council, led by Mullah Muhammad Omar and operating around the southern Pakistani city of Quetta, was directly responsible for a wave of violence in once relatively placid parts of northern and western Afghanistan. A recent string of attacks killed troops from Italy and Germany, pivotal American allies that are facing strong opposition to the Afghan war at home.

These assessments echo a recent report by Gen. Stanley A. McChrystal, the top military commander in Afghanistan, in portraying the Taliban as an increasingly sophisticated shadow government that sees itself on the cusp of victory in the war-ravaged nation. McChrystal's report describes how Omar's insurgency has appointed shadow governors in most provinces of Afghanistan, levies taxes, establishes Islamic courts there and conducts a formal review of its military campaign each winter.

American officials say they believe that the Taliban leadership in Pakistan still gets support from parts of the Directorate for Inter-Services Intelligence, Pakistan's military spy service. The ISI has been the Taliban's off-again-on-again benefactor for more than a decade, and some of its senior officials see Omar as a valuable asset should the United States leave Afghanistan and the Taliban regain power.

The issue of the Taliban leadership council, or shura, in Quetta is now at the top of the Obama administration's agenda in its meetings with Pakistani officials, including high-level discussions in New York this week. At the same time, American officials face a frustrating paradox: the more the administration wrestles publicly with how substantial and lasting a military commitment to make to Afghanistan, the more the ISI is likely to strengthen bonds to the Taliban as Pakistan hedges its bets.

American officials have long complained that senior Taliban leaders operating from Quetta, the capital of Baluchistan province, provide money, military supplies and strategic planning guidance to the Taliban in the south of Afghanistan, where most of the nearly 68,000 American forces are deployed.

But since NATO's offensive into the Taliban-dominated south this spring, the insurgents have surprised American commanders by stepping up attacks against allied troops elsewhere in the country to throw NATO off balance and create the perception of spreading violence that neither the allied military nor the civilian Afghan government in Kabul can control.

“;The Taliban is trying to create trouble elsewhere to alleviate pressure”; in the south, said one senior American intelligence official. “;They've outmaneuvered us time and time again.”;

The issue has opened fresh rifts between the United States and Pakistan over how to combat the Taliban leadership council in Quetta. American officials have voiced new and unusually public criticism of Pakistan's role in abetting the growing Afghan insurgency, reviving tensions that seemed to have eased after the two countries worked closely to track and kill Baitullah Mehsud, the leader of the Pakistani Taliban, in an American missile strike in Pakistan's tribal areas last month.

McChrystal said in his assessment, which was made public on Monday, “;Senior leaders of the major Afghan insurgent groups are based in Pakistan, are linked with al-Qaida and other violent extremist groups,”; and are reportedly aided by “;some elements”; of the ISI.

The U.S. ambassador to Pakistan, Anne W. Patterson, said in a recent interview with the McClatchy newspapers that the Pakistani government was “;certainly reluctant to take action”; against the leadership of the Afghan insurgency.

Pakistani officials take issue with that, adding that the United States overstates the threat posed by the Quetta shura, possibly because the American understanding of the situation is distorted by vague and self-serving intelligence provided by Afghanistan's spy service.

A senior Pakistani official said that the United States had asked Pakistan in recent years to round up 10 Taliban leaders in Quetta. Of those 10, six were killed or captured by the Pakistanis, two were probably in Afghanistan and the remaining two presented no threat.

“;Pakistan has said it's willing to act when given actionable intelligence,”; said the official, who spoke on condition of anonymity because he was not authorized to speak publicly on the matter. “;We have made substantial progress in the last year or so against the Quetta shura.”;

Pakistani officials also said that a move against militant leaders in Quetta risked inciting public anger throughout Baluchistan, a region that has long had a tense relationship with Pakistan's government in Islamabad. Omar, a reclusive cleric, recently rallied his troops with a boastful message timed for the Muslim holiday of Id al-Fitr. In the message, he taunted his American adversaries for ignoring the lessons of past military failures in Afghanistan, including the invasion of Alexander the Great's army. And he bragged that the Taliban had emerged as a nationalistic movement that “;is approaching the edge of victory.”;

A half-dozen American military, intelligence and diplomatic officials said in interviews that the Taliban leadership in Baluchistan, which abuts the portion of southern Afghanistan where most of the fighting is taking place, is increasing its strategic direction over the insurgency.

“;The Taliban inner shura in Baluchistan is certainly trying to exercise greater command and control over the Taliban in Afghanistan,”; said one American official in Afghanistan, who spoke on condition of anonymity because his assessment involved classified intelligence.

The official said that Mullah Abdullah Zakir, a former inmate at the American military prison in Guantanamo Bay, Cuba, who is now a top Taliban lieutenant, was involved in replacing Taliban shadow governors and commanders, as well as reorganizing the Taliban throughout the country. “;The Quetta shura—you can't knock on their clubhouse door,”; said a Western diplomat in Islamabad. “;It's much more of an amorphous group that as best we can tell moves around. They go to Karachi, they go to Quetta, they go across the border.”;

American officials grudgingly acknowledge the Taliban's skill at using guerrilla-style attacks to manipulate public impressions of the insurgency. “;We assess that the primary focus of attacks in northern provinces such as Kunduz is to create a perception that the insurgency is spreading like wildfire,”; the American official in Afghanistan said. “;But I think it's more of an 'information operations' success than a substantive one of holding any territory.”;

Another American intelligence official who follows Pakistan closely said the insurgents had sought to exploit allied countries' political vulnerabilities, like elections in Germany on Sunday. “;The Taliban have proven themselves capable of strategic planning,”; the official said.

McChrystal said in a telephone interview on Wednesday that he had been surprised by “;the growth of the shadow government, the growth of its coercion and its growth into the north and west.”;

Germany, which has suffered 33 combat deaths in Afghanistan, has remained committed to the Afghan mission, although it has placed strict limits on where its soldiers can serve, refusing to send them to the south.

But that commitment is now being hotly debated in the coming parliamentary elections, after an airstrike called in by a German commander this month. The NATO airstrike, directed at two tanker trucks carrying alliance fuel that had been hijacked by the Taliban, killed scores of people; the number of dead civilians remains unclear.

Other allies are also rethinking their presence in Afghanistan. A bomb that killed six Italian soldiers in Kabul last Thursday prompted Prime Minister Silvio Berlusconi of Italy to declare that his nation had begun planning to “;bring our young men home as soon as possible.”; Italy has 3,100 troops in Afghanistan.