Nasir al-Wahishi, al-Qaida's second in command, was killed in a U.S. airstrike earlier this month, the White House confirmed on Tuesday, according to the Associated Press.

Al-Wahishi had headed the terror network's Yemeni branch, which refers to itself as "al-Qaida in the Arabian Peninsula" and is widely considered the group's most dangerous outlet; his death dealt the organization its "biggest blow since the killing of Osama bin Laden," the newswire judged.

The terrorist was al Qaida's "leading light" and being groomed to one day to take over its leadership from current global chief, Ayman al-Zawahiri, CNN terrorism analyst Paul Cruickshank told the news network. Al-Wahishi had been responsible for the deaths of scores of Yemenis and Westerners, including U.S. citizens, National Security Council spokesman Ned Price noted.

"While (al-Qaida in the Arabian Peninsula), al-Qaida and their affiliates will remain persistent in their efforts to threaten the United States, our partners and our interests, his death removes from the battlefield an experienced terrorist leader and brings us closer to degrading and ultimately defeating those groups," Price said.

Al-Wahishi was only the latest in a series of high-ranking figures from al-Qaida's Yemeni branch who have been killed by U.S. drone attacks over the past five months, the AP recalled. The group's top ideologue and a senior military commander also died as the United States intensified its campaign to keep al-Qaida in the Arabian Peninsula from taking further "advantage of (Yemen's) chronic chaos," the newswire added.

Vowing revenge for al-Wahishi's death, meanwhile, al-Qaida on Wednesday killed two alleged Saudi spies, local residents told Reuters. The victims had been accused of planting tracking devices which aided U.S. forces as they pinpointed the location of their drone strike.

"They executed two Saudis, named al-Mutairi and al-Khaledi," an unidentified source told the British news service. "They put the two men on the corniche in the city of Mukalla ... they opened fire at them in front of a big group of residents."