CIA director Leon Panetta defended the use of unmanned aircraft to target Al-Qaeda militants on Monday and said President Barack Obama's policies had severely disrupted the network's leadership.
In his first speech since taking over as head of the Central Intelligence Agency in February, Panetta told a luncheon in Los Angeles that counter-terrorism and defeating Al-Qaeda remained the agency's top priority.
"Al-Qaeda remains the most serious security threat that we face ... to US interests and our allies overseas," Panetta told the gathering organized by the Pacific Council on International Policy in Los Angeles.
Panetta said Obama's stated aim to "disrupt, dismantle and defeat" Al-Qaeda had already resulted in "serious pressure" being brought to bear on the network's leaders, believed to be hiding in Pakistan's border regions.
"There is ample evidence that the strategy set by the president and his national security team is in fact working," Panetta said.
"We do not expect to let up on that strategy. I am convinced that our efforts in that part of the world are seriously disrupting every operation that Al-Qaeda is trying to conduct and is interfering with their ability to establish plans to come at this country and we will continue that effort."
Responding to a question, Panetta said unmanned drone strikes -- whose use has caused tension with Pakistan -- had been "very effective" in targeting Al-Qaeda's leadership.
"I think it does suffice to say that these operations have been very effective," Panetta said.
"It is very precise, it's very limited in terms of collateral damage and very frankly, it's the only game in town in terms of confronting and trying to disrupt the Al-Qaeda leadership."
Predator drones run by the CIA are regularly flown covertly in Pakistan, targeting Al-Qaeda militants. Officials say the US military does not participate in the armed drones program inside Pakistan.
Pakistani officials say the drone strikes, which have killed more than 390 people in about 42 attacks since August 2008, violate its territorial sovereignty and deepen resentment in the nuclear-armed nation.