The new Director of the CIA, David Patraeus, says the United States faces a long-term threat from al-Qaeda networks and its affiliates around the world. He however, said, the network's core operation has been weakened and every loss to al-Qaeda leadership appears to have created a window of vulnerability. Exploiting that window would however, require a sustained, focused effort, he said. Mr. Patraeus was addressing a joint hearing of Congressional intelligence committees in Washington.