WASHINGTON (AFP) - A small contingent of US military trainers have begun a training programme aimed at turning Pakistan's Frontier Corps into an effective counter-insurgency force, a US military official said Thursday. About 25 US military personnel last week began training Pakistani army trainers at a location in Pakistan outside the troubled tribal areas where the Frontier Corps operates, the official said, speaking on condition of anonymity. "It has started. It is a train-the-trainer mission," the official said, emphasizing that the Americans would not directly train the Frontier Corps , only their Pakistani army instructors. Recruited from the tribal areas and led by Pakistani army officers, the 80,000-member Frontier Corps historically has been poorly armed and trained. The aim is "basically to train the Frontier Corps in counter-insurgency warfare to make them more effective in the tribal areas," the official said. The politically sensitive programme had been stalled for months by negotiations between the US and Pakistani military. The official attributed the delay to difficulties in getting the facilities needed to conduct the training. "What is important here is that the Pakistani government recognizes they have a challenge with extremists inside their own country," said Pentagon spokesman Bryan Whitman. "Clearly they are looking for a variety of means to address it," he said. Meanwhile, fewer foreign fighters are slipping into Afghanistan since Pakistan launched its offensive in August against Al-Qaeda and Taliban militants in border tribal regions, the Pentagon said Wednesday. In a media briefing, US Defence Department spokesman Geoff Morrell welcomed "stepped-up operations" by the Pakistani military in Peshawar, and in Swat in particular, over the past two months. "It is stepped up not just in terms of tempo, but in terms of effectiveness," Morrell said. "As a result, we have seen some improvement in the flow of foreign fighters across the border into Afghanistan." He said the assessment came from US sources, but he gave no figures as to how many fewer foreign militants might be crossing the frontier since the Pakistani offensive - launched amid strong US pressure - began. It appears that Pakistani operations are not only more frequent, but also "more effective," with "more forces, more resources, perhaps a better strategy" being dedicated to the mission, he said. The Pakistan military said in late September that more than 1,000 militants - including Al-Qaeda's operational commander in the region, Egyptian Abu Saeed Al-Masri - have been killed in its offensive in Bajaur. Washington and Kabul say militants use the remote border areas of Pakistan to launch attacks on US-led and NATO troops deployed in Afghanistan.