The official, who spoke on the condition of anonymity, said Saturday Rahman was killed on August 22 in Pakistan's northwestern tribal region of Waziristan — a known refuge for Taliban and al-Qaida-linked militants.
The official would not say how Rahman was killed.
Pakistani security officials said on August 22 that a U.S. drone strike that day killed four suspected militants near the town of Mir Ali in North Waziristan.
Rahman rose to al-Qaida's number two spot after U.S. special operations forces killed the network's leader, Osama bin Laden, during a raid on his Pakistan compound in May. In June, al-Qaida picked Ayman al-Zawahri to succeed bin Laden as head of the terror organization.
Atiyah Abd al-Rahman was a Libyan national with close ties to late al-Qaida leader Osama bin Laden.
Rahman was on the U.S. State Department's “wanted” list for his ties to the militant group.
Al-Qaida's second in command was believed to have been in his 30's when, the U.S. says, he was killed Monday. The State Department says Rahman was a teenager when he joined bin Laden in Afghanistan in the 1980's.
Over the years, he rose through the ranks of the militant group — serving in roles that included explosives expert, recruiter, liaison and emissary in Iran.
In 2006 the Washington Post said a letter recovered from an al-Qaida safehouse in Iraq placed the group's leadership in Pakistan's border region. The newspaper said the letter was signed “Atiyah.” Counter-terrorism officials believed this was a reference to Rahman.