Intense operations have put top al-Qaeda leaders under extreme pressure and "many of them are on the run," a top American intelligence officer has claimed.
CIA Director Leon Panetta said, "Our counter-terrorism operation have put put top al-Qaeda leaders under intense pressure and much of their network has been disrupted."
Without referring to covert drone attacks believed to be launched from Pakistani soil, Panetta said in his address at the University of Oklahoma, local TV reports said.
Saying that US was at war with al-Qaeda and its affiliated terrorist organisations, America's top spy claimed that operations in tribal areas of Pakistan has killed more than half of al-Qaeda's top 20 commanders.
He said that American efforts both in Afghanistan and Pakistan were aimed at hitting command and control centres of the al-Qaeda.
Panetta's claim comes as Pakistani forces with the help of CIA have captured some top Taliban commanders, including the outfits Nos 2 Mulla Abdul Ghani Baradar.
US drone attacks have also claimed to kill more than 600 al-Qaeda and Taliban militants in less than three years.
Warning that it was a war, the spy chief said al-Qaeda would keep on coming at the Americans and said new intelligence indicated that Osama bin Laden led outfit was changing its tactics and trying to launch attacks on the US through people with no history of terrorist activities.