Evidence is mounting that the U.S. killed al Qaeda’s number two official in an attack in eastern Yemen three days ago.

Reports in the Yemeni press and in social media favored by jihadis claim that Nasir al-Wuhayshi, who serves both as head of al Qaeda in the Arabian Peninsula and second in command of al Qaeda Central, was killed Friday by a U.S. drone strike in Mukalla, Yemen.

One U.S. counterterrorism official confirmed that al-Wuhayshi had been targeted, while an intelligence official said “we are looking to confirm his death.” A third official, when asked about reports of al-Wuhayshi’s death, said, "No one is calling jackpot yet."

The attack was one of two this weekend against leaders of the terror group's main affiliates. On Sunday morning local time, U.S. aircraft bombed a location in Ajdabiya in eastern Libya while targeting the leader of al Qaeda in the Islamic Maghreb (AQIM), Mokhtar Belmokhtar. Libyan government officials say Belmokhtar was killed, but there has been no U.S. confirmation of Belmokhtar's death.

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Belmokhtar, 43, rose to international prominence for allegedly masterminding a spectacular terrorist attack on an Algerian natural gas plant in January 2013. His forces took more than 800 people hostage at the Tigantourine gas facility, executing 39 hostages, including three Americans. The facility was recaptured by Algerian forces days later.

The U.S. strike on al-Wuhayshi, however, would be more significant, since al Qaeda in the Arabian Peninsula (AQAP) is al Qaeda’s most important affiliate and al-Wuhayshi was said to be “operations manager” of al Qaeda Central, reporting directly to Ayman al-Zawahiri.

Zawahiri assumed command of the terror group after Osama bin Laden’s 2011 death, and retains leadership of al Qaeda in Pakistan, but his mobility is limited and he is unable to plan much of anything, said a U.S. counterterrorism official. On the other hand, said the official, al-Wuhayshi, "by virtue of where he is," can plan external operations against the West.

Wuhayshi, a 38-year-old Yemeni, served as secretary to bin Laden at the time of the September 11 attacks and then rose in the al Qaeda hierarchy. After 9-11, he fled Afghanistan as U.S. forces moved in, and was arrested after crossing the border into Iran. Iranian authorities turned him over to authorities in his native Yemen, where he escaped from prison and reconnected with al Qaeda.

With the death of a succession of No. 2 candidates in 2011 and 2012, al-Wuhayshi rose to the second most important position in the terror group last year. The U.S. has posted a $10 million reward for his capture.

Wuhayshi’s primary organization, AQAP, was responsible for the Charlie Hebdo attack in Paris this January that killed a dozen people, say U.S. and French officials. Yemen is also home to bombmakers who have tried to take down U.S. and French airliners.

Unofficial reports of al-Wuhayshi’s death are now surfacing on the internet. "Social media is lighting up all over Yemen with the same message, that he is dead," said a U.S. official. Yemeni media are reporting that not only is al-Wuhayshi dead but his replacement has been selected.

AQIM social media, meanwhile, continues to claim that the strike in Libya did not kill Belmokhtar. One U.S. official said getting confirmation of Belmokhtar's death would be more difficult since the attack on his compound "was not a surgical strike." His location was flattened by multiple 500-pound bombs.