Senior leaders of al Qaeda are using sanctuaries in Pakistan's lawless frontier regions to plan new terror attacks and funnel money, manpower and guidance to affiliates around the world, according to a top American military commander. Gen. David Petraeus, who oversees the wars in Iraq and Afghanistan, said in an interview that Pakistan has become the nerve center of al Qaeda's global operations, allowing the terror group to re-establish its organizational structure and build stronger ties to al Qaeda offshoots in Iraq, Yemen, Somalia, North Africa and parts of Europe. The comments underscore a growing U.S. belief that Pakistan has displaced Afghanistan as al Qaeda's main stronghold. "It is the headquarters of the al Qaeda senior leadership," said the general, who took the helm of the military's Central Command last fall. In the interview, Gen. Petraeus also warned of difficult months ahead in Afghanistan, saying Taliban militants are moving weapons and forces into areas where the U.S. is adding troops, planning a "surge" of their own to counter the U.S. plan. The commander said the U.S. had intelligence showing that the Taliban were deploying new fighters to southern Afghanistan, appointing new local commanders, and prepositioning weapons and other supplies. "We have every expectation that the Taliban will fight to retain the sanctuaries and safe havens that they've been able to establish," he said. Senior Obama administration officials have spoken publicly for weeks about the threat posed by Pakistan. In late March, President Barack Obama said that Pakistan's lawless border region had "become the most dangerous place in the world" for Americans. Pakistani officials have acknowledged that their country is facing a growing threat from al Qaeda, the Taliban and other armed Islamist groups. Appearing at the White House on Wednesday with President Hamid Karzai of Afghanistan and Secretary of State Hillary Clinton, Pakistan's President Asif Ali Zardari pledged to "stand with our brother Karzai and the people of Afghanistan against this common threat, this menace, which I have called a cancer." Pakistani Ambassador Hussein Haqqani said in an email that his government is "determined to eliminate Al Qaeda and the terrorist Taliban." He added, "We have launched a major offensive against the Taliban and look forward to acting on any actionable intelligence shared with us by our American partners." U.S. officials once believed that years of strikes had broken al Qaeda's leadership into smaller, less effective splinter groups. But in the interview, Gen. Petraeus said U.S. intelligence information suggested that al Qaeda has re-emerged as a centrally directed organization capable of helping to plan attacks in other countries. "There is a degree of hierarchy, there is a degree of interconnection, and there is certainly a flow of people, money, expertise, explosives and knowledge," he said. A U.S. soldier returns fire from a base camp on a Taliban position in the Korengal Valley of Afghanistan's Kunar Province on Friday. Gen. Petraeus painted a picture of a globalized al Qaeda that maintains extensive logistical and communications links to terror groups in Morocco, Somalia and other countries. He said militants and supplies pass through southern Iran, helped by Sunni Arab "facilitators" in the predominantly Shiite Persian country. A ring of Tunisian suicide bombers who were recently apprehended in Iraq appear to have received their directions from al Qaeda figures in Pakistan as well, he said. "There's absolutely no question about these links," he said. American intelligence agencies have used drones to fire missiles at dozens of militant targets inside Pakistan in recent months, killing several top al Qaeda figures. But U.S. officials acknowledge that al Qaeda's senior leadership has survived those attacks. Al Qaeda's resurgence in Pakistan is posing a policy dilemma for the Obama administration and senior U.S. commanders like Gen. Petraeus. Pakistan's government won't allow U.S. military personnel into the country. That is forcing the U.S. either to strike targets from a distance, which doesn't always work, or to rely on Pakistan's own security personnel, who have so far been largely unwilling to venture into al Qaeda's remote sanctuaries. The Pentagon has looked at possible changes in Afghanistan amid concern over the course of the conflict -- some of which have met resistance from current military leaders including Gen. Petraeus. A task force formed by Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, is conducting a broad review, according to a copy of its agenda. Defense Secretary Robert Gates is expected to appoint an additional general to handle day-to-day operations there, senior defense officials say. A spokesman for Gen. Petraeus has declined to comment. Gen. Petraeus spent the past week in Washington as part of the Obama administration's summit with presidents Karzai and Zardari. He said the Pakistani Taliban appear to have overreached by sending fighters into the Buner District, just 60 miles from the capital. Echoing recent comments from top Obama administration officials, he said Pakistan's government, military and people seemed to have finally accepted that the Taliban pose a threat to their country's future and must be dealt with. "There's a sense of collective determination to respond forcefully," he said. "The Taliban challenged the very writ of the Pakistani government, and that's being taken very seriously." Still, he said it was too soon to gauge the full magnitude or duration of the Pakistani response.