A US government official says a top al-Qaeda operative has been killed in a drone attack in western Pakistan. The official would not immediately identify the target of the attack, which he said occurred very recently. However, he said it was neither Osama bin Laden nor Ayman al-Zawahiri, the terrorist networks top two leaders. The official spoke on condition of anonymity because he was not authorized to discuss the classified program publicly. The drone attack was first reported on Wednesday night by NBC News. Intelligence officials have confirmed that the pace of attacks by armed unmanned aerial vehicles has increased during the Obama administration.