WASHINGTON - The outgoing top US military commander in Afghanistan says that Taliban attacks increased 50 percent in April and that stabilizing Afghanistan will be impossible without a more robust military campaign against what he called insurgent havens in Pakistan. "What's missing is action to keep pressure on the insurgents," Gen. Dan  McNeill, who departed June 3 after 16 months commanding NATO's International Security Assistance Force, or ISAF, said at a Pentagon news conference on Friday, according to an account published in The Washington Post Sunday. For example, Pakistan's army chief, Gen. Ashfaq Kiyani, has for four months failed to agree to attend a meeting that Afghanistan, Pakistan and the United States have held in recent years on border problems. The Taliban is "resurgent in the region," particularly in sanctuaries in Pakistan, and as a result "it's going to be difficult to take on this insurgent group . . . in the broader sort of way," he added. Afghanistan has 364 districts, and last year about 70 percent of all attacks took place in 40, or about 10 percent, of those districts, McNeill said. For the first half of this year, he said, about 76 percent of attacks took place in virtually the same 40 districts, with some shifts in Farah and Nimruz provinces. The district data has helped drive the deployment of NATO forces, with the 24th Marine Expeditionary Unit focusing on a district in southern Helmand that shows extensive enemy activity. "We knew it was a dark hole and we had to get to it; we simply didn't have the force," said McNeill, noting that ISAF remains short of combat troops, helicopters, and intelligence and surveillance equipment. More worrisome than the Taliban expansion in Pakistan is the threat of more cooperation between homegrown insurgents and outside extremist groups, McNeill asserted. "The greatest risk is the possibility of collusion between the insurgents who are indigenous to that region and the more intractable, the more extreme terrorists who are taking up residence there in the North-West Frontier Province of Pakistan, he said. McNeill criticized Pakistani efforts to crack down on that threat, and -- offering his unofficial view -- described the political situation in Islamabad as "dysfunctional." He also criticized efforts by the Pakistan government to negotiate peace deals with insurgents on the frontier, saying past agreements have led to increased attacks across the border in Afghanistan. McNeill said the 50 percent increase in attacks in eastern Afghanistan in April compared with the same month last year is "directly attributable to the lack of pressure on the other side of the border." McNeill declined to endorse a U.S.-funded programme to train and equip Pakistan's Frontier Corps, which guards the border, questioning the effectiveness and loyalty of the tribally recruited guards. "It takes well-trained, well-equipped forces, disciplined to take this thing on," he said. "The Pakistanis, in using the Frontier Corps as a military entity to take on the insurgency, will find some challenges." McNeill raised two instances in which the guards have shot and killed U.S. soldiers, saying he would be "forever scarred" by what he described as the "assassination" of Maj. Larry Bauguess of the 82nd Airborne Division after a border meeting last spring. Another soldier was shot in the neck and killed by a Frontier Corps guard in 2002, he said.