Al Qaeda's No. 2 leader, Atiyah Abd al-Rahman, has been killed in Pakistan, a U.S. official tells Fox News.
Al-Rahman was a Libyan national who was considered Al Qaeda's operational leader before rising to the No. 2 spot following Usama bin Laden's death in May.
Al-Rahman's death is a big blow to the terrorist group and comes as U.S. officials have said in the aftermath of bin Laden's killing that a few more high-profile deaths could break Al Qaeda's back.
The official, who spoke on condition of anonymity, says al-Rahman was killed Aug. 22 in the Pakistani tribal region of Waziristan. That's the same day a US drone strike in Waziristan.
Defense Secretary Leon Panetta said last month that Al Qaeda's defeat was within reach if the U.S. could mount a string of successful attacks on the group's weakened leadership.
"Now is the moment, following what happened with bin Laden, to put maximum pressure on them," Panetta said, "because I do believe that if we continue this effort we can really cripple Al Qaeda as a major threat."
Since bin Laden's death, Al Qaeda's structure has been unsettled and U.S. officials have hoped to capitalize on that. The more uncertain the leadership, the harder it is for Al Qaeda to operate covertly and plan attacks.
Bin Laden's longtime deputy, Ayman al-Zawahiri, is running the group but is considered a divisive figure who lacks the founder's charisma and ability to galvanize Al Qaeda's disparate franchises.
Rahman has been thought to be dead before. Last year, there were reports that Rahman was killed in a drone strike but neither senior U.S. administration officials nor Al Qaeda ever confirmed them.
Al-Rahman was allowed to move freely in and out of Iran as part of that arrangement and has been operating out of Waziristan for some time, officials have said.
Born in Libya, al-Rahman joined bin Laden as a teenager in Afghanistan to fight the Soviet Union.
After Navy SEALs killed bin Laden, they found evidence of al-Rahman's role as operational chief, U.S. officials have said.
The Associated Press contributed to this report