WASHINGTON The United States has to make sure that there are strong enough governments in place in Afghanistan and Pakistan working with the Americans to eliminate terrorist networks in the region, President Barack Obama has said. Our mission, first and foremost, is to dismantle and destroy al-Qaeda and its affiliates so that they cant attack the United States. The reason were there in the first place is because 3,000 Americans were killed from an attack launched in that region. We are not going to have that repeated, he said in response to a question at a White House news briefing on Thursday. In order to achieve that, we have to make sure that we have a stable Afghan government, and we also have to make sure that weve got a Pakistani government that is working effectively with us to dismantle these networks, Obama said. What we then said was we would put in additional troops to provide the time and the space for the Afghan government to build up its security capacities, to clear and hold population centres that are critical, to drive back the Taliban, to break their momentum, and that beginning next year we would begin a transition phase in which the Afghan government is taking more and more responsibility for its own security, he added.