President Barack Obama has said United States cooperation with Pakistan will be continued to curb the activities of the terrorists. Pakistan and Afghanistan would not let alone in the fight against terrorism and militancy, the US President reiterated in his press conference and television interview after accepting the Nobel Prize in a ceremony here. He said he has set the deadline of troops pullout from Afghanistan to inform the Afghan government the United States would not take responsibility of their security forever. Afghan security forces have to take responsibility of their national security. Obama said the allied forces could stay in Afghanistan for several years.