Al-Rahman was a Libyan national who was considered al-Qaida's operational leader before rising to the No. 2 spot following Osama 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-Qaida's back.
The official, who spoke on condition of anonymity to discuss sensitive intelligence operations, 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.