Under growing pressure from US missile strikes, the Al-Qaeda terror network is relying more heavily on local insurgent groups along the Pakistan border to house training camps that are growing smaller and more mobile, according to counterterrorism officials and analysts. The changes in the terror group's training operations – often hidden inside walled compounds deep in Pakistan's mountains - have made them increasingly difficult to target by US intelligence forces as they have stepped up drone attacks over the past year. While the training still includes forays into deserted hillsides to practice planting and detonating explosives, Al-Qaeda trainers are now also taking their instruction on the road, moving temporary training operations from compound to compound, where fellow insurgents welcome them. The attacks on the camps, which have become an integral part of the Obama administration's war against the terror group, also risk civilian casualties - which in turn have inflamed anti-American sentiment among the Pakistanis, critical allies in widening the anti-terror campaign. The camps took on a heightened profile in recent months as US investigators probed the case of accused New York terror suspect Najibullah Zazi. The Afghan émigré reportedly fled to Pakistan late last year and traveled to Peshawar, in the northwest frontier, where he received training on weapons and explosives. Counterterrorism officials estimate that Zazi is one of 100 to 150 Westerners who have gone to the Pakistan border region for terror training in the last year. Their ability to filter in and out of the isolated camps has fueled fears that “sleeper” operatives bearing US or western passports are traveling back and forth with ease to train and plot attacks destined within America's borders. Several officials provided details about the camps on condition of anonymity to discuss intelligence matters and other experts acknowledged the trends. Counterterrorism officials and analysts say an exact number of camps along the border is impossible to pin down, but say they are easily in the dozens. Vahid Brown, a researcher at the Combating Terrorism Center at West Point, the elite military academy, said that recent trends suggest Al-Qaeda is now moving its trainers and resources around, operating within camps operated by a variety of militant groups, including some that have long-standing relationships with Pakistan's Directorate for Inter-Services Intelligence (ISI) and military intelligence. That indirect protection offers Al-Qaeda some degree of security it might not have on its own, he said. Militant groups that have provided Al-Qaeda with training centers include Jaish-e-Mohammed, Lashkar-e-Janghvi, and Tehrik-e-Taliban Pakistan – factions that have connections to Taliban insurgents and have also been linked to brutal attacks against the government. Jaish-e-Mohammed was known for ties to the Pakistani military, but more has recently sided with Taliban militants to fight security forces along the border. The groups have reportedly hosted Al-Qaeda training in compounds in Waziristan and Swat Valley, and officials have more recently started seeing similar activities in the Punjab province, where some militant groups have stronger ties to the Pakistani government. “Al-Qaeda doesn't have local relationships that allow for these kinds of camps to be operated in more or less full view,” said Brown. “It makes more sense for Al-Qaeda strategy to not put their eggs into one stable basket and try to be its own training provider, but rather to use its portable training resources and assets as a means of extending the violence.” Gone are the days, said officials and analysts, when Al-Qaeda leaders filled sprawling open-air training camps inside Afghanistan with terror recruits from around the world. Such bases as Tarnack Farms, a massive camp outside Kandahar's airport where Osama Bin Laden was believed to have plotted the Sept. 11 attacks, contained busy firing ranges and other facilities, but were also easy to detect. Now, smaller temporary camps hidden inside stark stone buildings blend in with surrounding nondescript mountain compounds that can house innocent civilians. “All you need is a shack or a house to learn how to fabricate explosives using homemade or commercially available ingredients,” said Bruce Hoffman, a counterterrorism expert at Georgetown University and a longtime government adviser. Hoffman adds that in these harder-to-find camps, “they're not training insurgents; they're training terrorists for deployment to the west. Some of them may be deployed in the insurgency, but I think it's obvious that their value to these groups is not fighting on the battlefield in South Asia but in being deployed back to their home or adopted countries as sleepers.” In a recently released Al-Qaeda Internet video filmed inside one nameless camp, a camera pans across open laptop computers and lingers on a sleeping bag covered with explosives and electronic equipment. Shelves are filled with canisters holding unknown material, as well as electronic scales, often used to measure explosives. Hanging from the walls are panoply of automatic weapons and other guns, and outside, spread across a blanket, lay rocket propelled grenade launchers and an ammunition display. According to the Washington-based Site Intelligence Group, which monitors militant Web sites and made the video available, the footage - posted on millitants' forums about a month ago - supposedly shows a training camp in Pakistan's Waziristan region. The anonymous Web poster, according to the Web site, suggested the video showed a camp where slain Al-Qaeda chemical weapons expert Abu Khabab al-Masri trained militants. According to Brown, the madrasas, which are historically nonviolent organizations, have also had long-standing ties with militants' groups. People within those nonviolent organizations, he said, will say, “if you want to be violent, you have to leave us, but here's an address and a letter of introduction” for a recruiter from one of the militant groups. Officials stress that even though the terror training is now far more mobile than it once was, it remains no less sophisticated or deadly. “Certainly their ambition is to mount headline-grabbing attacks, visual spectaculars,” said Richard Barrett, coordinator of the monitoring team for the UN's Al-Qaeda and Taliban Sanctions Committee. “They are extremely suspicious of anyone coming in and are very careful of security, so it's quite difficult to make these contacts and to develop them.” The militants, he said, “are patient people. They will wait for the tide to turn or a lucky break.”