Admiral: Troops alone will not yield victory in Afghanistan WASHINGTON (CNN) -- The U.S. is "running out of time" to win the war in Afghanistan, and sending in more troops will not guarantee victory, the chairman of the Joint Chiefs of Staff warned Congress on Wednesday. Adm. Michael Mullen made his statement to the House Armed Services Committee a day after President Bush announced the deployment of 4,500 additional troops to the poor, war-ravaged nation. Mullen said he is convinced the war can be won, but the U.S. urgently needs to improve its nation-building initiatives and its cross-border strategy with Pakistan. "We can't kill our way to victory, and no armed force anywhere -- no matter how good -- can deliver these keys alone. It requires teamwork and cooperation," Mullen said, according to prepared remarks for his appearance before the House Armed Services Committee. Mullen's remarks came a day before the seventh anniversary of the September 11 terror attacks on the World Trade Center and the Pentagon, which prompted the U.S.-led invasion of Afghanistan. The Taliban government harboring the al Qaeda movement that conducted the 9/11 attacks was overthrown soon after U.S. and British troops entered the country in October 2001, but the militants have re-established their presence there. And Mullen says they've grown "bolder." Cross-border attacks into Afghanistan by militants in Pakistan's tribal region are a problem, and the U.S. has deployed Predator drones to attack targets in Pakistan. Last week, U.S. troops entered Pakistan, a move that prompted condemnation from Islamabad. Mullen stressed that Afghanistan can't be referenced without "speaking of Pakistan," where, he says, the militant groups collaborate and communicate better, launch more sophisticated attacks, employ foreign fighters and use civilians as human shields. "In my view these two nations are inextricably linked in a common insurgency that crosses the border between them," he said, adding that he plans "to commission a new, more comprehensive strategy for the region, one that covers both sides of the border." "I have pressed hard on my counterparts in Pakistan to do more against extremists, and to let us do more to help them," he said. The conflict is exacerbated, he said, by the "poor and struggling Afghan economy," as well as the drug trade and "significant political uncertainty in Pakistan." These factors present a "complex, difficult struggle." Mullen said he has urged the "growth and training" of Afghan forces and U.S. military officials recommend the deployment of a Marine battalion this fall and another army unit early next year, which Bush announced Tuesday. The deployments are not enough for now but are "a good start," Mullen said. There are more than 30,000 U.S. troops under coalition and NATO commands in Afghanistan. "Frankly, I judge the risk of not sending them too great a risk to ignore. My expectation is that they will need to perform both the training mission and combat and combat support missions simultaneously until such time that we can provide additional troops. I cannot at this point say when that might be," he said. He is confident that Afghan security forces can be trained and developed. "In fact, they are on track to reach a total end strength of 162,000 troops by 2010. The Marines conducting their training are doing a phenomenal job," he said. At the same time, Mullen warned "that no amount of troops in no amount of time can ever achieve all the objectives we seek." Until Afghan security forces gain the backing of local leaders to improve security, "we will only be as much as a crutch -- and a temporary one at that," the admiral said. "We can hunt down and kill extremists as they cross over the border from Pakistan, as I watched us do during a daylong trip to the Korengal valley in July. But until we work more closely with the Pakistani government to eliminate the safe havens from which they operate, the enemy will only keep coming," he said. Mullen also said roads, schools and courts can be built and repaired, but that is not enough either. Afghanistan needs more experts in commerce, agriculture, jurisprudence and education. The nation also needs "foreign investment, alternative crops, sound governance and the rule of law." Until then, Mullen said, courts, schools and other government buildings "will remain but empty shells."